services: Add oci-service-type.

This patch implements a generalization of the
oci-container-service-type, which consequently is made deprecated.  The
oci-service-type, in addition to all the features from the
oci-container-service-type, can now provision OCI networks and volumes.
It only handles OCI objects creation, the user is supposed to handle
state once the objects are provsioned.

It currently supports two different OCI runtimes: Docker and rootless
Podman.  Both runtimes are tested to make sure provisioned containers
can connect to each other through provisioned networks and can
read/write data with provisioned volumes.

At last the Scheme API is thought to facilitate the implementation of a
Guix Home service in the future.

* gnu/build/oci-containers.scm: New file containg OCI runtime business
logic used in OCI backed Shepherd services.
oci-read-lines
(oci-system*,oci-object-exists?,oci-object-service-available?
oci-image-load,oci-log-verbose,oci-container-execlp,oci-object-create):
New procedures.
* gnu/local.mk: Add it.
* gnu/services/containers.scm (list-of-oci-containers?,
list-of-oci-networks?,list-of-oci-volumes?,%oci-supported-runtimes,
oci-runtime?,oci-runtime-system-environment,oci-runtime-system-extra-arguments,
oci-runtime-system-requirement,oci-runtime-cli,oci-runtime-system-cli,
oci-runtime-home-cli,oci-runtime-name,oci-runtime-group,
oci-container-shepherd-name,oci-networks-shepherd-name,
oci-networks-home-shepherd-name,oci-volumes-shepherd-name,
oci-volumes-home-shepherd-name,oci-container-configuration->options,
oci-network-configuration->options,oci-volume-configuration->options,
oci-container-shepherd-service,oci-objects-merge-lst,oci-extension-merge,
oci-service-accounts,oci-service-profile,oci-service-subids,
oci-configuration->shepherd-services,oci-configuration-extend): New
procedures.
(image-reference): Implement unambiguous naming convention, that paired
with the new implementation for listing caches images with docker ls or
podman ls, allows for more efficient image caching.
(oci-container-configuration)[user,group]: Change default-type to
maybe-string, since by default containers will run under the user and
group declared in oci-configuration records. When unset the
oci-service-type will derive their value from the OCI runtime state.
[runtime,host-environment,environment,shepherd-actions,ports,extra-arguments]:
define a predicate and use it as a type in the configuration.  This
way errors are reported with source location information.
(lower-manifest): Defer to caller the logic of setting up an image tag.
(lower-oci-image): Rename to load-oci-image-state.
(oci-runtime-state): Intermediate representation of the OCI runtime
details. It is supposed to be an internal API.
(oci-state): Intermediate representation of the OCI provisioning state,
such as containers and networks. It is supposed to be an internal API.
(oci-container-invocation): Intermediate representation of the OCI
runtime run command to start a container. It is supposed to be an
internal API.
(%oci-image-loader): Rename to oci-image-loader and use
oci-runtime-state and (gnu build oci-containers).
(oci-container-shepherd-service): Use oci-state and oci-runtime-state,
add command-line action.
(oci-network-configuration,oci-volume-configuration,oci-configuration,
oci-extension): New record types.
(oci-service-type): New service-type.
* doc/guix.texi: Document it.
* gnu/tests/containers.scm: Test it.
* gnu/services/docker.scm: Deprecate the oci-container-service-type.

Change-Id: I656b3db85832e42d53072fcbfb91d1226f39ef38
Modified-by: Maxim Cournoyer <maxim@guixotic.coop>
Signed-off-by: Maxim Cournoyer <maxim@guixotic.coop>

2 files changed, 1177 insertions, 200 deletions

diff --git a/gnu/services/containers.scm b/gnu/services/containers.scm
index 24f31c756b8..c9eadea9b47 100644
--- a/gnu/services/containers.scm
+++ b/gnu/services/containers.scm
@@ -35,12 +35,15 @@
   #:use-module (guix diagnostics)
   #:use-module (guix gexp)
   #:use-module (guix i18n)
+  #:use-module (guix modules)
   #:use-module (guix monads)
   #:use-module (guix packages)
   #:use-module (guix profiles)
   #:use-module ((guix scripts pack) #:prefix pack:)
+  #:use-module (guix records)
   #:use-module (guix store)
   #:use-module (srfi srfi-1)
+  #:use-module (ice-9 format)
   #:use-module (ice-9 match)
   #:export (rootless-podman-configuration
             rootless-podman-configuration?
@@ -96,8 +99,82 @@
             oci-container-configuration-workdir
             oci-container-configuration-extra-arguments
 
+            list-of-oci-containers?
+            list-of-oci-networks?
+            list-of-oci-volumes?
+
+            %oci-supported-runtimes
+            oci-runtime?
+            oci-runtime-system-environment
+            oci-runtime-system-extra-arguments
+            oci-runtime-system-requirement
+            oci-runtime-cli
+            oci-runtime-system-cli
+            oci-runtime-home-cli
+            oci-runtime-name
+            oci-runtime-group
+
+            oci-network-configuration
+            oci-network-configuration?
+            oci-network-configuration-fields
+            oci-network-configuration-name
+            oci-network-configuration-driver
+            oci-network-configuration-gateway
+            oci-network-configuration-internal?
+            oci-network-configuration-ip-range
+            oci-network-configuration-ipam-driver
+            oci-network-configuration-ipv6?
+            oci-network-configuration-subnet
+            oci-network-configuration-labels
+            oci-network-configuration-extra-arguments
+
+            oci-volume-configuration
+            oci-volume-configuration?
+            oci-volume-configuration-fields
+            oci-volume-configuration-name
+            oci-volume-configuration-labels
+            oci-volume-configuration-extra-arguments
+
+            oci-configuration
+            oci-configuration?
+            oci-configuration-fields
+            oci-configuration-runtime
+            oci-configuration-runtime-cli
+            oci-configuration-runtime-extra-arguments
+            oci-configuration-user
+            oci-configuration-group
+            oci-configuration-containers
+            oci-configuration-networks
+            oci-configuration-volumes
+            oci-configuration-verbose?
+            oci-configuration-valid?
+
+            oci-extension
+            oci-extension?
+            oci-extension-fields
+            oci-extension-containers
+            oci-extension-networks
+            oci-extension-volumes
+
+            oci-container-shepherd-name
+            oci-networks-shepherd-name
+            oci-networks-home-shepherd-name
+            oci-volumes-shepherd-name
+            oci-volumes-home-shepherd-name
+
+            oci-container-configuration->options
+            oci-network-configuration->options
+            oci-volume-configuration->options
+
             oci-container-shepherd-service
-            %oci-container-accounts))
+            oci-objects-merge-lst
+            oci-extension-merge
+            oci-service-type
+            oci-service-accounts
+            oci-service-profile
+            oci-service-subids
+            oci-configuration->shepherd-services
+            oci-configuration-extend))
 
 (define (gexp-or-string? value)
   (or (gexp? value)
@@ -296,9 +373,42 @@ to be shared.  This service sets it so.")
 
 
 ;;;
-;;; OCI container.
+;;; OCI provisioning service.
 ;;;
 
+(define %oci-supported-runtimes
+  '(docker podman))
+
+(define (oci-runtime-system-requirement runtime)
+  "Return a list of Shepherd service names required by a given OCI runtime,
+before it is able to run containers."
+  (if (eq? 'podman runtime)
+      '(cgroups2-fs-owner cgroups2-limits
+        rootless-podman-shared-root-fs user-processes)
+      '(dockerd user-processes)))
+
+(define (oci-runtime-name runtime)
+  "Return a human readable name for a given OCI runtime."
+  (if (eq? 'podman runtime)
+      "Podman" "Docker"))
+
+(define (oci-runtime-group runtime maybe-group)
+  "Implement the logic behind selection of the group that is to be used by
+Shepherd to execute OCI commands."
+  (if (maybe-value-set? maybe-group)
+      maybe-group
+      (if (eq? 'podman runtime)
+          "cgroup"
+          "docker")))
+
+(define (oci-runtime? value)
+  (unless (member value %oci-supported-runtimes)
+    (raise
+     (formatted-message
+      (G_ "OCI runtime must be a symbol and one of ~a,
+but ~a was found") %oci-supported-runtimes value)))
+  (symbol? value))
+
 (define (oci-sanitize-pair pair delimiter)
   (define (valid? member)
     (or (string? member)
@@ -332,21 +442,41 @@ found!")
   ;; '(("HOME" . "/home/nobody") "JAVA_HOME=/java")
   (oci-sanitize-mixed-list "host-environment" value "="))
 
+(define (oci-container-host-environment? value)
+  (list? (oci-sanitize-host-environment value)))
+
 (define (oci-sanitize-environment value)
   ;; Expected spec format:
   ;; '(("HOME" . "/home/nobody") "JAVA_HOME=/java")
   (oci-sanitize-mixed-list "environment" value "="))
 
+(define (oci-container-environment? value)
+  (list? (oci-sanitize-environment value)))
+
 (define (oci-sanitize-ports value)
   ;; Expected spec format:
   ;; '(("8088" . "80") "2022:22")
   (oci-sanitize-mixed-list "ports" value ":"))
 
+(define (oci-container-ports? value)
+  (list? (oci-sanitize-ports value)))
+
 (define (oci-sanitize-volumes value)
   ;; Expected spec format:
   ;; '(("/mnt/dir" . "/dir") "/run/current-system/profile:/java")
   (oci-sanitize-mixed-list "volumes" value ":"))
 
+(define (oci-container-volumes? value)
+  (list? (oci-sanitize-volumes value)))
+
+(define (oci-sanitize-labels value)
+  ;; Expected spec format:
+  ;; '(("foo" . "bar") "foo=bar")
+  (oci-sanitize-mixed-list "labels" value "="))
+
+(define (oci-object-labels? value)
+  (list? (oci-sanitize-labels value)))
+
 (define (oci-sanitize-shepherd-actions value)
   (map
    (lambda (el)
@@ -358,6 +488,9 @@ found!")
 but ~a was found") el))))
    value))
 
+(define (oci-container-shepherd-actions? value)
+  (list? (oci-sanitize-shepherd-actions value)))
+
 (define (oci-sanitize-extra-arguments value)
   (define (valid? member)
     (or (string? member)
@@ -373,11 +506,19 @@ but ~a was found") el))))
 but ~a was found") el))))
    value))
 
+(define (oci-object-extra-arguments? value)
+  (list? (oci-sanitize-extra-arguments value)))
+
 (define (oci-image-reference image)
-  (if (string? image)
-      image
-      (string-append (oci-image-repository image)
-                     ":" (oci-image-tag image))))
+  "Return a string OCI image reference representing IMAGE."
+  (define reference
+    (if (string? image)
+        image
+        (string-append (oci-image-repository image)
+                       ":" (oci-image-tag image))))
+  (if (> (length (string-split reference #\/)) 1)
+        reference
+        (string-append "localhost/" reference)))
 
 (define (oci-lowerable-image? image)
   (or (manifest? image)
@@ -392,7 +533,19 @@ but ~a was found") el))))
 (define list-of-symbols?
   (list-of symbol?))
 
+(define (list-of-oci-records? name predicate value)
+  (map
+   (lambda (el)
+     (if (predicate el)
+         el
+         (raise
+          (formatted-message
+           (G_ "~a contains an illegal value: ~a") name el))))
+   value))
+
 (define-maybe/no-serialization string)
+(define-maybe/no-serialization package)
+(define-maybe/no-serialization subid-range)
 
 (define-configuration/no-serialization oci-image
   (repository
@@ -437,11 +590,15 @@ value will be ignored.")
 
 (define-configuration/no-serialization oci-container-configuration
   (user
-   (string "oci-container")
-   "The user under whose authority docker commands will be run.")
+   (maybe-string)
+   "The user name under whose authority OCI commands will be run.  This field will
+override the @code{user} field of @code{oci-configuration}.")
   (group
-   (string "docker")
-   "The group under whose authority docker commands will be run.")
+   (maybe-string)
+   "The group name under whose authority OCI commands will be run.  When
+using the @code{'podman} OCI runtime, this field will be ignored and the
+default group of the user configured in the @code{user} field will be used.
+This field will override the @code{group} field of @code{oci-configuration}.")
   (command
    (list-of-strings '())
    "Overwrite the default command (@code{CMD}) of the image.")
@@ -449,11 +606,11 @@ value will be ignored.")
    (maybe-string)
    "Overwrite the default entrypoint (@code{ENTRYPOINT}) of the image.")
   (host-environment
-   (list '())
+   (oci-container-host-environment '())
    "Set environment variables in the host environment where @command{docker run}
-is invoked.  This is especially useful to pass secrets from the host to the
-container without having them on the @command{docker run}'s command line: by
-setting the @code{MYSQL_PASSWORD} on the host and by passing
+or @command{podman run} are invoked.  This is especially useful to pass secrets
+from the host to the container without having them on the OCI runtime command line,
+for example: by setting the @code{MYSQL_PASSWORD} on the host and by passing
 @code{--env MYSQL_PASSWORD} through the @code{extra-arguments} field, it is
 possible to securely set values in the container environment.  This field's
 value can be a list of pairs or strings, even mixed:
@@ -467,7 +624,7 @@ Pair members can be strings, gexps or file-like objects. Strings are passed
 directly to @code{make-forkexec-constructor}."
    (sanitizer oci-sanitize-host-environment))
   (environment
-   (list '())
+   (oci-container-environment '())
    "Set environment variables inside the container.  This can be a list of pairs
 or strings, even mixed:
 
@@ -477,15 +634,16 @@ or strings, even mixed:
 @end lisp
 
 Pair members can be strings, gexps or file-like objects. Strings are passed
-directly to the Docker CLI.  You can refer to the
-@url{https://docs.docker.com/engine/reference/commandline/run/#env,upstream}
-documentation for semantics."
+directly to the OCI runtime CLI.  You can refer to the
+@url{https://docs.docker.com/engine/reference/commandline/run/#env,Docker}
+or @url{https://docs.podman.io/en/stable/markdown/podman-run.1.html#env-e-env,Podman}
+upstream documentation for semantics."
    (sanitizer oci-sanitize-environment))
   (image
    (string-or-oci-image)
    "The image used to build the container.  It can be a string or an
-@code{oci-image} record.  Strings are resolved by the Docker
-Engine, and follow the usual format
+@code{oci-image} record.  Strings are resolved by the OCI runtime,
+and follow the usual format
 @code{myregistry.local:5000/testing/test-image:tag}.")
   (provision
    (maybe-string)
@@ -508,15 +666,15 @@ is @code{#f} the service has to be started manually with @command{herd start}.")
    "Whether to restart the service when it stops, for instance when the
 underlying process dies.")
   (shepherd-actions
-   (list '())
+   (oci-container-shepherd-actions '())
    "This is a list of @code{shepherd-action} records defining actions supported
 by the service."
    (sanitizer oci-sanitize-shepherd-actions))
   (network
    (maybe-string)
-   "Set a Docker network for the spawned container.")
+   "Set an OCI network for the spawned container.")
   (ports
-   (list '())
+   (oci-container-ports '())
    "Set the port or port ranges to expose from the spawned container.  This can
 be a list of pairs or strings, even mixed:
 
@@ -526,12 +684,13 @@ be a list of pairs or strings, even mixed:
 @end lisp
 
 Pair members can be strings, gexps or file-like objects. Strings are passed
-directly to the Docker CLI.  You can refer to the
-@url{https://docs.docker.com/engine/reference/commandline/run/#publish,upstream}
-documentation for semantics."
+directly to the OCI runtime CLI.  You can refer to the
+@url{https://docs.docker.com/engine/reference/commandline/run/#publish,Docker}
+or @url{https://docs.podman.io/en/stable/markdown/podman-run.1.html#publish-p-ip-hostport-containerport-protocol,Podman}
+upstream documentation for semantics."
    (sanitizer oci-sanitize-ports))
   (volumes
-   (list '())
+   (oci-container-volumes '())
    "Set volume mappings for the spawned container.  This can be a
 list of pairs or strings, even mixed:
 
@@ -541,71 +700,342 @@ list of pairs or strings, even mixed:
 @end lisp
 
 Pair members can be strings, gexps or file-like objects. Strings are passed
-directly to the Docker CLI.  You can refer to the
-@url{https://docs.docker.com/engine/reference/commandline/run/#volume,upstream}
-documentation for semantics."
+directly to the OCI runtime CLI.  You can refer to the
+@url{https://docs.docker.com/engine/reference/commandline/run/#volume,Docker}
+or @url{https://docs.podman.io/en/stable/markdown/podman-run.1.html#volume-v-source-volume-host-dir-container-dir-options,Podman}
+upstream documentation for semantics."
    (sanitizer oci-sanitize-volumes))
   (container-user
    (maybe-string)
    "Set the current user inside the spawned container.  You can refer to the
-@url{https://docs.docker.com/engine/reference/run/#user,upstream}
-documentation for semantics.")
+@url{https://docs.docker.com/engine/reference/run/#user,Docker}
+or @url{https://docs.podman.io/en/stable/markdown/podman-run.1.html#user-u-user-group,Podman}
+upstream documentation for semantics.")
   (workdir
    (maybe-string)
-   "Set the current working for the spawned Shepherd service.
+   "Set the current working directory for the spawned Shepherd service.
 You can refer to the
-@url{https://docs.docker.com/engine/reference/run/#workdir,upstream}
-documentation for semantics.")
+@url{https://docs.docker.com/engine/reference/run/#workdir,Docker}
+or @url{https://docs.podman.io/en/stable/markdown/podman-run.1.html#workdir-w-dir,Podman}
+upstream documentation for semantics.")
   (extra-arguments
-   (list '())
+   (oci-object-extra-arguments '())
    "A list of strings, gexps or file-like objects that will be directly passed
-to the @command{docker run} invokation."
+to the @command{docker run} or @command{podman run} invocation."
    (sanitizer oci-sanitize-extra-arguments)))
 
-(define oci-container-configuration->options
-  (lambda (config)
-    (let ((entrypoint
-           (oci-container-configuration-entrypoint config))
-          (network
-           (oci-container-configuration-network config))
-          (user
-           (oci-container-configuration-container-user config))
-          (workdir
-           (oci-container-configuration-workdir config)))
-      (apply append
-             (filter (compose not unspecified?)
-                     `(,(if (maybe-value-set? entrypoint)
-                            `("--entrypoint" ,entrypoint)
-                            '())
-                       ,(append-map
-                         (lambda (spec)
-                           (list "--env" spec))
-                         (oci-container-configuration-environment config))
-                       ,(if (maybe-value-set? network)
-                            `("--network" ,network)
-                            '())
-                       ,(if (maybe-value-set? user)
-                            `("--user" ,user)
-                            '())
-                       ,(if (maybe-value-set? workdir)
-                            `("--workdir" ,workdir)
-                            '())
-                       ,(append-map
-                         (lambda (spec)
-                           (list "-p" spec))
-                         (oci-container-configuration-ports config))
-                       ,(append-map
-                         (lambda (spec)
-                           (list "-v" spec))
-                         (oci-container-configuration-volumes config))))))))
+(define (list-of-oci-containers? value)
+  (list-of-oci-records? "containers" oci-container-configuration? value))
+
+(define-configuration/no-serialization oci-volume-configuration
+  (name
+   (string)
+   "The name of the OCI volume to provision.")
+  (labels
+   (oci-object-labels '())
+   "The list of labels that will be used to tag the current volume."
+   (sanitizer oci-sanitize-labels))
+  (extra-arguments
+   (oci-object-extra-arguments '())
+   "A list of strings, gexps or file-like objects that will be directly passed
+to the @command{docker volume create} or @command{podman volume create}
+invocation."
+   (sanitizer oci-sanitize-extra-arguments)))
+
+(define (list-of-oci-volumes? value)
+  (list-of-oci-records? "volumes" oci-volume-configuration? value))
+
+(define-configuration/no-serialization oci-network-configuration
+  (name
+   (string)
+   "The name of the OCI network to provision.")
+  (driver
+   (maybe-string)
+   "The driver to manage the network.")
+  (gateway
+   (maybe-string)
+   "IPv4 or IPv6 gateway for the subnet.")
+  (internal?
+   (boolean #f)
+   "Restrict external access to the network")
+  (ip-range
+   (maybe-string)
+   "Allocate container ip from a sub-range in CIDR format.")
+  (ipam-driver
+   (maybe-string)
+   "IP Address Management Driver.")
+  (ipv6?
+   (boolean #f)
+   "Enable IPv6 networking.")
+  (subnet
+   (maybe-string)
+   "Subnet in CIDR format that represents a network segment.")
+  (labels
+   (oci-object-labels '())
+   "The list of labels that will be used to tag the current volume."
+   (sanitizer oci-sanitize-labels))
+  (extra-arguments
+   (oci-object-extra-arguments '())
+   "A list of strings, gexps or file-like objects that will be directly passed
+to the @command{docker network create} or @command{podman network create}
+invocation."
+   (sanitizer oci-sanitize-extra-arguments)))
+
+(define (list-of-oci-networks? value)
+  (list-of-oci-records? "networks" oci-network-configuration? value))
+
+(define (package-or-string? value)
+  (or (package? value) (string? value)))
+
+(define-maybe/no-serialization package-or-string)
+
+(define-configuration/no-serialization oci-configuration
+  (runtime
+   (oci-runtime 'docker)
+   "The OCI runtime to use to run commands.  It can be either @code{'docker} or
+@code{'podman}.")
+  (runtime-cli
+   (maybe-package-or-string)
+   "The OCI runtime command line to be installed in the system profile and used
+to provision OCI resources, it can be either a package or a string representing
+an absolute file name to the runtime binary entrypoint.  When unset it will default
+to @code{docker-cli} package for the @code{'docker} runtime or to @code{podman}
+package for the @code{'podman} runtime.")
+  (runtime-extra-arguments
+   (list '())
+   "A list of strings, gexps or file-like objects that will be placed
+after each @command{docker} or @command{podman} invokation.")
+  (user
+   (string "oci-container")
+   "The user name under whose authority OCI runtime commands will be run.")
+  (group
+   (maybe-string)
+   "The group name under whose authority OCI commands will be run.  When
+using the @code{'podman} OCI runtime, this field will be ignored and the
+default group of the user configured in the @code{user} field will be used.")
+  (subuids-range
+   (maybe-subid-range)
+   "An optional @code{subid-range} record allocating subuids for the user from
+the @code{user} field.  When unset, with the rootless Podman OCI runtime, it
+defaults to @code{(subid-range (name \"oci-container\"))}.")
+  (subgids-range
+   (maybe-subid-range)
+   "An optional @code{subid-range} record allocating subgids for the user from
+the @code{user} field.  When unset, with the rootless Podman OCI runtime, it
+defaults to @code{(subid-range (name \"oci-container\"))}.")
+  (containers
+   (list-of-oci-containers '())
+   "The list of @code{oci-container-configuration} records representing the
+containers to provision.  The use of the @code{oci-extension} record should
+be preferred for most cases.")
+  (networks
+   (list-of-oci-networks '())
+   "The list of @code{oci-network-configuration} records representing the
+networks to provision.  The use of the @code{oci-extension} record should
+be preferred for most cases.")
+  (volumes
+   (list-of-oci-volumes '())
+   "The list of @code{oci-volume-configuration} records representing the
+volumes to provision.  The use of the @code{oci-extension} record should
+be preferred for most cases.")
+  (verbose?
+   (boolean #f)
+   "When true, additional output will be printed, allowing to better follow the
+flow of execution.")
+  (home-service?
+   (boolean for-home?)
+   "This is an internal field denoting whether this configuration is used in a
+Guix Home context, as opposed to the default Guix System context."))
 
-(define* (get-keyword-value args keyword #:key (default #f))
-  (let ((kv (memq keyword args)))
-    (if (and kv (>= (length kv) 2))
-        (cadr kv)
-        default)))
+(define (oci-runtime-system-environment runtime user)
+  (if (eq? runtime 'podman)
+      (list
+       #~(string-append
+          "HOME=" (passwd:dir (getpwnam #$user))))
+      #~()))
+
+(define (oci-runtime-cli runtime runtime-cli profile-directory)
+  "Return a gexp that, when lowered, evaluates to the  of the OCI
+runtime command requested by the user."
+  (if (string? runtime-cli)
+      ;; It is a user defined absolute file name.
+      runtime-cli
+      #~(string-append
+         #$(if (maybe-value-set? runtime-cli)
+               runtime-cli
+               profile-directory)
+         #$(if (eq? 'podman runtime)
+               "/bin/podman"
+               "/bin/docker"))))
+
+(define* (oci-runtime-system-cli config #:key (profile-directory "/run/current-system/profile"))
+  (let ((runtime-cli
+         (oci-configuration-runtime-cli config))
+        (runtime
+         (oci-configuration-runtime config)))
+    (oci-runtime-cli runtime runtime-cli profile-directory)))
+
+(define (oci-runtime-home-cli config)
+  (let ((runtime-cli
+         (oci-configuration-runtime-cli config))
+        (runtime
+         (oci-configuration-runtime config)))
+    (oci-runtime-cli runtime runtime-cli
+                     (string-append (getenv "HOME")
+                                    "/.guix-home/profile"))))
+
+(define-configuration/no-serialization oci-extension
+  (containers
+   (list-of-oci-containers '())
+   "The list of @code{oci-container-configuration} records representing the
+containers to add.")
+  (networks
+   (list-of-oci-networks '())
+   "The list of @code{oci-network-configuration} records representing the
+networks to add.")
+  (volumes
+   (list-of-oci-volumes '())
+   "The list of @code{oci-volume-configuration} records representing the
+volumes to add."))
+
+(define (oci-image->container-name image)
+  "Infer the name of an OCI backed Shepherd service from its OCI image."
+  (basename
+   (if (string? image)
+       (first (string-split image #\:))
+       (oci-image-repository image))))
+
+(define (oci-command-line-shepherd-action object-name invocation entrypoint)
+  "Return a Shepherd action printing a given INVOCATION of an OCI command for the
+given OBJECT-NAME."
+  (shepherd-action
+   (name 'command-line)
+   (documentation
+    (format #f "Prints ~a's OCI runtime command line invocation."
+            object-name))
+   (procedure
+    #~(lambda _
+        (format #t "Entrypoint:~%~a~%" #$entrypoint)
+        (format #t "Invocation:~%~a~%" #$invocation)))))
+
+(define (oci-container-shepherd-name runtime config)
+  "Return the name of an OCI backed Shepherd service based on CONFIG.
+The name configured in the configuration record is returned when
+CONFIG's name field has a value, otherwise a name is inferred from CONFIG's
+image field."
+  (define name (oci-container-configuration-provision config))
+  (define image (oci-container-configuration-image config))
+
+  (if (maybe-value-set? name)
+      name
+      (string-append (symbol->string runtime) "-"
+                     (oci-image->container-name image))))
+
+(define (oci-networks-shepherd-name runtime)
+  "Return the name of the OCI networks provisioning Shepherd service based on
+RUNTIME."
+  (string-append (symbol->string runtime) "-networks"))
+
+(define (oci-volumes-shepherd-name runtime)
+  "Return the name of the OCI volumes provisioning Shepherd service based on
+RUNTIME."
+  (string-append (symbol->string runtime) "-volumes"))
+
+(define (oci-networks-home-shepherd-name runtime)
+  "Return the name of the OCI volumes provisioning Home Shepherd service based on
+RUNTIME."
+  (string-append "home-" (oci-networks-shepherd-name runtime)))
+
+(define (oci-volumes-home-shepherd-name runtime)
+  "Return the name of the OCI volumes provisioning Home Shepherd service based on
+RUNTIME."
+  (string-append "home-" (oci-volumes-shepherd-name runtime)))
+
+(define (oci-container-configuration->options config)
+  "Map CONFIG, an oci-container-configuration record, to a gexp that, upon
+lowering, will be evaluated to a list of strings containing command line options
+for the OCI runtime run command."
+  (let ((entrypoint (oci-container-configuration-entrypoint config))
+        (network (oci-container-configuration-network config))
+        (user (oci-container-configuration-container-user config))
+        (workdir (oci-container-configuration-workdir config)))
+    (apply append
+           (filter (compose not unspecified?)
+                   (list (if (maybe-value-set? entrypoint)
+                             `("--entrypoint" ,entrypoint)
+                             '())
+                         (append-map
+                          (lambda (spec)
+                            (list "--env" spec))
+                          (oci-container-configuration-environment config))
+                         (if (maybe-value-set? network)
+                             `("--network" ,network)
+                             '())
+                         (if (maybe-value-set? user)
+                             `("--user" ,user)
+                             '())
+                         (if (maybe-value-set? workdir)
+                             `("--workdir" ,workdir)
+                             '())
+                         (append-map
+                          (lambda (spec)
+                            (list "-p" spec))
+                          (oci-container-configuration-ports config))
+                         (append-map
+                          (lambda (spec)
+                            (list "-v" spec))
+                          (oci-container-configuration-volumes config)))))))
+
+(define (oci-network-configuration->options config)
+  "Map CONFIG, an oci-network-configuration record, to a gexp that, upon
+lowering, will be evaluated to a list of strings containing command line options
+for the OCI runtime network create command."
+  (let ((driver (oci-network-configuration-driver config))
+        (gateway (oci-network-configuration-gateway config))
+        (internal? (oci-network-configuration-internal? config))
+        (ip-range (oci-network-configuration-ip-range config))
+        (ipam-driver (oci-network-configuration-ipam-driver config))
+        (ipv6? (oci-network-configuration-ipv6? config))
+        (subnet (oci-network-configuration-subnet config)))
+    (apply append
+           (filter (compose not unspecified?)
+                   (list (if (maybe-value-set? driver)
+                             `("--driver" ,driver)
+                             '())
+                         (if (maybe-value-set? gateway)
+                             `("--gateway" ,gateway)
+                             '())
+                         (if internal?
+                             `("--internal")
+                             '())
+                         (if (maybe-value-set? ip-range)
+                             `("--ip-range" ,ip-range)
+                             '())
+                         (if (maybe-value-set? ipam-driver)
+                             `("--ipam-driver" ,ipam-driver)
+                             '())
+                         (if ipv6?
+                             `("--ipv6")
+                             '())
+                         (if (maybe-value-set? subnet)
+                             `("--subnet" ,subnet)
+                             '())
+                         (append-map
+                          (lambda (spec)
+                            (list "--label" spec))
+                          (oci-network-configuration-labels config)))))))
+
+(define (oci-volume-configuration->options config)
+  "Map CONFIG, an oci-volume-configuration record, to a gexp that, upon
+lowering, will be evaluated to a list of strings containing command line options
+for the OCI runtime volume create command."
+  (append-map
+   (lambda (spec)
+     (list "--label" spec))
+   (oci-volume-configuration-labels config)))
 
 (define (lower-operating-system os target system)
+  "Lower OS, an operating-system record, into a tarball containing an OCI image."
   (mlet* %store-monad
       ((tarball
         (lower-object
@@ -614,24 +1044,11 @@ to the @command{docker run} invokation."
          #:target target)))
     (return tarball)))
 
-(define (lower-manifest name image target system)
-  (define value (oci-image-value image))
-  (define options (oci-image-pack-options image))
-  (define image-reference
-    (oci-image-reference image))
-  (define image-tag
-    (let* ((extra-options
-            (get-keyword-value options #:extra-options))
-           (image-tag-option
-            (and extra-options
-                 (get-keyword-value extra-options #:image-tag))))
-      (if image-tag-option
-          '()
-          `(#:extra-options (#:image-tag ,image-reference)))))
-
+(define (lower-manifest name value options image-reference
+                        target system grafts?)
+  "Lower VALUE, a manifest record, into a tarball containing an OCI image."
   (mlet* %store-monad
-      ((_ (set-grafting
-           (oci-image-grafts? image)))
+      ((_ (set-grafting grafts?))
        (guile (set-guile-for-build (default-guile)))
        (profile
         (profile-derivation value
@@ -642,14 +1059,11 @@ to the @command{docker run} invokation."
        (tarball (apply pack:docker-image
                        `(,name ,profile
                          ,@options
-                         ,@image-tag
                          #:localstatedir? #t))))
     (return tarball)))
 
-(define (lower-oci-image name image)
-  (define value (oci-image-value image))
-  (define image-target (oci-image-target image))
-  (define image-system (oci-image-system image))
+(define (lower-oci-image-state name value options reference
+                               image-target image-system grafts?)
   (define target
     (if (maybe-value-set? image-target)
         image-target
@@ -662,7 +1076,8 @@ to the @command{docker run} invokation."
    (run-with-store store
      (match value
        ((? manifest? value)
-        (lower-manifest name image target system))
+        (lower-manifest name value options reference
+                        target system grafts?))
        ((? operating-system? value)
         (lower-operating-system value target system))
        ((or (? gexp? value)
@@ -677,113 +1092,661 @@ operating-system, gexp or file-like records but ~a was found")
      #:target target
      #:system system)))
 
-(define (%oci-image-loader name image tag)
-  (let ((docker (file-append docker-cli "/bin/docker"))
-        (tarball (lower-oci-image name image)))
-    (with-imported-modules '((guix build utils))
-      (program-file (format #f "~a-image-loader" name)
-       #~(begin
-           (use-modules (guix build utils)
-                        (ice-9 popen)
-                        (ice-9 rdelim))
+(define (lower-oci-image name image)
+  "Lower IMAGE, a oci-image record, into a tarball containing an OCI image."
+  (lower-oci-image-state
+   name
+   (oci-image-value image)
+   (oci-image-pack-options image)
+   (oci-image-reference image)
+   (oci-image-target image)
+   (oci-image-system image)
+   (oci-image-grafts? image)))
+
+(define-record-type* <oci-runtime-state>
+  oci-runtime-state
+  make-oci-runtime-state
+  oci-runtime-state?
+  this-oci-runtime-state
 
-           (format #t "Loading image for ~a from ~a...~%" #$name #$tarball)
-           (define line
-             (read-line
-              (open-input-pipe
-               (string-append #$docker " load -i " #$tarball))))
+  (runtime                  oci-runtime-state-runtime
+                            (default 'docker))
+  (runtime-cli              oci-runtime-state-runtime-cli)
+  (user                     oci-runtime-state-user)
+  (group                    oci-runtime-state-group)
+  (runtime-environment      oci-runtime-state-runtime-environment
+                            (default #~()))
+  (runtime-requirement      oci-runtime-state-runtime-requirement
+                            (default '()))
+  (runtime-extra-arguments  oci-runtime-state-runtime-extra-arguments
+                            (default '())))
 
-           (unless (or (eof-object? line)
-                       (string-null? line))
-             (format #t "~a~%" line)
-             (let ((repository&tag
-                    (string-drop line
-                                 (string-length
-                                   "Loaded image: "))))
+(define-record-type* <oci-state>
+  oci-state
+  make-oci-state
+  oci-state?
+  this-oci-state
 
-               (invoke #$docker "tag" repository&tag #$tag)
-               (format #t "Tagged ~a with ~a...~%" #$tarball #$tag))))))))
+  (networks                 oci-state-networks)
+  (volumes                  oci-state-volumes)
+  (containers               oci-state-containers)
+  (networks-name            oci-state-networks-name
+                            (default #f))
+  (volumes-name             oci-state-volumes-name
+                            (default #f))
+  (networks-requirement     oci-state-networks-requirement
+                            (default '()))
+  (volumes-requirement      oci-state-volumes-requirement
+                            (default '()))
+  (containers-requirement   oci-state-containers-requirement
+                            (default '())))
 
-(define (oci-container-shepherd-service config)
-  (define (guess-name name image)
-    (if (maybe-value-set? name)
-        name
-        (string-append "docker-"
-                       (basename
-                        (if (string? image)
-                            (first (string-split image #\:))
-                            (oci-image-repository image))))))
+(define-record-type* <oci-container-invocation>
+  oci-container-invocation
+  make-oci-container-invocation
+  oci-container-invocation?
+  this-oci-container-invocation
+
+  (runtime                  oci-container-invocation-runtime
+                            (default 'docker))
+  (runtime-cli              oci-container-invocation-runtime-cli)
+  (name                     oci-container-invocation-name)
+  (command                  oci-container-invocation-command
+                            (default '()))
+  (image-reference          oci-container-invocation-image-reference)
+  (options                  oci-container-invocation-options
+                            (default '()))
+  (run-extra-arguments      oci-container-invocation-run-extra-arguments
+                            (default '()))
+  (runtime-extra-arguments  oci-container-invocation-runtime-extra-arguments
+                            (default '())))
+
+(define (oci-container-configuration->oci-container-invocation runtime-state
+                                                               config)
+  (oci-container-invocation
+   (runtime (oci-runtime-state-runtime runtime-state))
+   (runtime-cli (oci-runtime-state-runtime-cli runtime-state))
+   (name
+    (oci-container-shepherd-name runtime config))
+   (command
+    (oci-container-configuration-command config))
+   (image-reference
+    (oci-image-reference (oci-container-configuration-image config)))
+   (options
+    (oci-container-configuration->options config))
+   (run-extra-arguments
+    (oci-container-configuration-extra-arguments config))
+   (runtime-extra-arguments
+    (oci-runtime-state-runtime-extra-arguments runtime-state))))
+
+(define* (oci-image-loader runtime-state name image tag #:key verbose?)
+  "Return a file-like object that, once lowered, will evaluate to a program able
+to load IMAGE through RUNTIME-CLI and to tag it with TAG afterwards."
+  (let ((tarball (lower-oci-image name image)))
+    (with-imported-modules (source-module-closure '((gnu build oci-containers)))
+      (program-file
+       (format #f "~a-image-loader" name)
+       #~(begin
+           (use-modules (gnu build oci-containers))
+           (oci-image-load '#$(oci-runtime-state-runtime runtime-state)
+                           #$(oci-runtime-state-runtime-cli runtime-state)
+                           #$tarball #$name #$tag
+                           #:verbose? #$verbose?))))))
 
-  (let* ((docker (file-append docker-cli "/bin/docker"))
-         (actions (oci-container-configuration-shepherd-actions config))
-         (auto-start?
-          (oci-container-configuration-auto-start? config))
-         (user (oci-container-configuration-user config))
-         (group (oci-container-configuration-group config))
-         (host-environment
-          (oci-container-configuration-host-environment config))
-         (command (oci-container-configuration-command config))
-         (log-file (oci-container-configuration-log-file config))
-         (provision (oci-container-configuration-provision config))
-         (requirement (oci-container-configuration-requirement config))
-         (respawn?
-          (oci-container-configuration-respawn? config))
-         (image (oci-container-configuration-image config))
-         (image-reference (oci-image-reference image))
-         (options (oci-container-configuration->options config))
-         (name (guess-name provision image))
-         (extra-arguments
-          (oci-container-configuration-extra-arguments config)))
+(define (oci-container-run-invocation container-invocation)
+  "Return a list representing the OCI runtime
+invocation for running containers."
+  ;; run [OPTIONS] IMAGE [COMMAND] [ARG...]
+  `(,(oci-container-invocation-runtime-cli container-invocation)
+    ,@(oci-container-invocation-runtime-extra-arguments container-invocation)
+    "run" "--rm"
+    ,@(if (eq? (oci-container-invocation-runtime container-invocation)
+               'podman)
+          ;; This is because podman takes some time to
+          ;; release container names.  --replace seems
+          ;; to be required to be able to restart services.
+          '("--replace")
+          '())
+    "--name" ,(oci-container-invocation-name container-invocation)
+    ,@(oci-container-invocation-options container-invocation)
+    ,@(oci-container-invocation-run-extra-arguments container-invocation)
+    ,(oci-container-invocation-image-reference container-invocation)
+    ,@(oci-container-invocation-command container-invocation)))
 
-    (shepherd-service (provision `(,(string->symbol name)))
-                      (requirement `(dockerd user-processes ,@requirement))
+(define* (oci-container-entrypoint name invocation
+                                   #:key verbose?
+                                   (pre-script #~()))
+  "Return a file-like object that, once lowered, will evaluate to the entrypoint
+for the Shepherd service that will run INVOCATION."
+  (program-file
+   (string-append "oci-entrypoint-" name)
+   (with-imported-modules (source-module-closure
+                           '((gnu build oci-containers)))
+     #~(begin
+         (use-modules (gnu build oci-containers)
+                      (srfi srfi-1))
+         (oci-container-execlp
+          (list #$@invocation)
+          #:verbose? #$verbose?
+          #:pre-script
+          (lambda _
+            (when (and #$verbose?
+                       (zero? (length '(#$@pre-script))))
+              (format #t "No pre script to run..."))
+            #$@pre-script))))))
+
+(define* (oci-container-shepherd-service state runtime-state config
+                                         #:key verbose?
+                                         networks?
+                                         volumes?)
+  "Return a Shepherd service object that will run the OCI container represented
+by CONFIG through RUNTIME-CLI."
+  (match-record config <oci-container-configuration>
+                (shepherd-actions auto-start? user group host-environment
+                 log-file requirement respawn? image)
+    (define runtime (oci-runtime-state-runtime runtime-state))
+    (define runtime-cli (oci-runtime-state-runtime-cli runtime-state))
+    (define image-reference (oci-image-reference image))
+    (define shepherd-name (oci-container-shepherd-name runtime config))
+    (define oci-container-user
+      (if (maybe-value-set? user)
+          user
+          (oci-runtime-state-user runtime-state)))
+    (define oci-container-group
+      (if (maybe-value-set? group)
+          group
+          (oci-runtime-state-group runtime-state)))
+    (define networks-service
+      (if networks?
+          (list
+           (string->symbol
+            (oci-state-networks-name state)))
+          '()))
+    (define volumes-service
+     (if volumes?
+         (list
+          (string->symbol
+           (oci-state-volumes-name state)))
+         '()))
+    (define oci-container-requirement
+      (append requirement
+              (oci-state-containers-requirement state)
+              (oci-runtime-state-runtime-requirement runtime-state)
+              networks-service
+              volumes-service))
+    (define environment-variables
+      #~(append
+         (list #$@host-environment)
+         (list #$@(oci-runtime-state-runtime-environment runtime-state))))
+    (define invocation
+      (oci-container-run-invocation
+       (oci-container-configuration->oci-container-invocation
+        runtime-state config)))
+    (define* (container-action command)
+      #~(lambda _
+          (fork+exec-command
+           (list #$@command)
+           #$@(if oci-container-user
+                  (list #:user oci-container-user)
+                  '())
+           #$@(if oci-container-group
+                  (list #:group oci-container-group)
+                  '())
+           #$@(if (maybe-value-set? log-file)
+                  (list #:log-file log-file)
+                  '())
+           #$@(if (and oci-container-user (eq? runtime 'podman))
+                  (list #:directory
+                        #~(passwd:dir
+                           (getpwnam #$oci-container-user)))
+                  '())
+           #:environment-variables
+           #$environment-variables)))
+    (define start-entrypoint
+      (oci-container-entrypoint
+       shepherd-name invocation
+       #:verbose? verbose?
+       #:pre-script
+       (if (oci-image? image)
+           #~((system*
+               #$(oci-image-loader
+                  runtime-state shepherd-name image
+                  image-reference
+                  #:verbose? verbose?)))
+           #~())))
+
+    (shepherd-service (provision `(,(string->symbol shepherd-name)))
+                      (requirement oci-container-requirement)
                       (respawn? respawn?)
                       (auto-start? auto-start?)
                       (documentation
                        (string-append
-                        "Docker backed Shepherd service for "
-                        (if (oci-image? image) name image) "."))
+                        (oci-runtime-name runtime)
+                        " backed Shepherd service for "
+                        (if (oci-image? image) shepherd-name image) "."))
                       (start
-                       #~(lambda ()
-                           #$@(if (oci-image? image)
-                                  #~((invoke #$(%oci-image-loader
-                                                name image image-reference)))
-                                  #~())
-                           (fork+exec-command
-                            ;; docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
-                            (list #$docker "run" "--rm" "--name" #$name
-                                  #$@options #$@extra-arguments
-                                  #$image-reference #$@command)
-                            #:user #$user
-                            #:group #$group
-                            #$@(if (maybe-value-set? log-file)
-                                   (list #:log-file log-file)
-                                   '())
-                            #:environment-variables
-                            (list #$@host-environment))))
+                       (container-action
+                        (list start-entrypoint)))
                       (stop
-                       #~(lambda _
-                           (invoke #$docker "rm" "-f" #$name)))
+                       (container-action
+                        (list
+                         (oci-container-entrypoint
+                          shepherd-name (list runtime-cli "rm" "-f" shepherd-name)
+                          #:verbose? verbose?))))
                       (actions
-                       (if (oci-image? image)
-                           '()
-                           (append
+                       (append
+                        (list
+                         (oci-command-line-shepherd-action
+                          shepherd-name #~(string-join (list #$@invocation) " ")
+                          start-entrypoint))
+                        (if (oci-image? image)
+                            '()
                             (list
                              (shepherd-action
                               (name 'pull)
                               (documentation
                                (format #f "Pull ~a's image (~a)."
-                                       name image))
+                                       shepherd-name image))
                               (procedure
-                               #~(lambda _
-                                   (invoke #$docker "pull" #$image)))))
-                            actions))))))
+                               (container-action
+                                (list
+                                 (oci-container-entrypoint
+                                  shepherd-name (list runtime-cli "pull" image)
+                                  #:verbose? verbose?)))))))
+                        shepherd-actions)))))
+
+(define (oci-object-create-invocation object runtime-cli name options
+                                      runtime-extra-arguments
+                                      create-extra-arguments)
+  "Return a gexp that, upon lowering, will evaluate to the OCI runtime
+invocation for creating networks and volumes."
+  ;; network|volume create [options] [NAME]
+  #~(list #$runtime-cli #$@runtime-extra-arguments #$object "create"
+          #$@options #$@create-extra-arguments #$name))
 
-(define %oci-container-accounts
+(define (format-oci-invocations invocations)
+  "Return a gexp that, upon lowering, will evaluate to a formatted message
+containing the INVOCATIONS that the OCI runtime will execute to provision
+networks or volumes."
+  #~(string-join (map (lambda (i) (string-join i " "))
+                      (list #$@invocations))
+                 "\n"))
+
+(define* (oci-object-create-script object runtime runtime-cli invocations
+                                   #:key verbose?)
+  "Return a file-like object that, once lowered, will evaluate to a program able
+to create OCI networks and volumes through RUNTIME-CLI."
+  (define runtime-string (symbol->string runtime))
+  (define runtime-name (oci-runtime-name runtime))
+  (with-imported-modules (source-module-closure
+                          '((gnu build oci-containers)))
+
+    (program-file
+     (string-append runtime-string "-" object "s-create.scm")
+     #~(begin
+         (use-modules (gnu build oci-containers))
+         (oci-object-create '#$runtime #$runtime-cli #$runtime-name
+                            #$object (list #$@invocations)
+                            #:verbose? #$verbose?)))))
+
+(define* (oci-object-shepherd-service object runtime-state name
+                                      oci-state-requirement invocations
+                                      #:key verbose?)
+  "Return a Shepherd service object that will provision the OBJECTs represented
+by INVOCATIONS through RUNTIME-STATE."
+  (match-record runtime-state <oci-runtime-state>
+                (runtime runtime-cli runtime-requirement user group
+                 runtime-environment)
+    (define entrypoint
+      (oci-object-create-script
+       object runtime runtime-cli invocations #:verbose? verbose?))
+    (define requirement
+      (append runtime-requirement oci-state-requirement))
+
+    (shepherd-service (provision (list (string->symbol name)))
+                      (requirement requirement)
+                      (one-shot? #t)
+                      (documentation
+                       (string-append
+                        (oci-runtime-name runtime) " " object
+                        " provisioning service"))
+                      (start
+                       #~(lambda _
+                           (fork+exec-command
+                            (list #$entrypoint)
+                            #$@(if user (list #:user user) '())
+                            #$@(if group (list #:group group) '())
+                            #:environment-variables
+                            (list #$@runtime-environment))))
+                      (actions
+                       (list
+                        (oci-command-line-shepherd-action
+                         name (format-oci-invocations invocations)
+                         entrypoint))))))
+
+(define* (oci-networks-shepherd-service state runtime-state
+                                        #:key verbose?)
+  "Return a Shepherd service object that will create the networks represented
+in STATE."
+  (define runtime-cli
+    (oci-runtime-state-runtime-cli runtime-state))
+  (define invocations
+    (map
+     (lambda (network)
+       (oci-object-create-invocation
+        "network" runtime-cli
+        (oci-network-configuration-name network)
+        (oci-network-configuration->options network)
+        (oci-runtime-state-runtime-extra-arguments runtime-state)
+        (oci-network-configuration-extra-arguments network)))
+     (oci-state-networks state)))
+
+  (oci-object-shepherd-service
+   "network" runtime-state (oci-state-networks-name state)
+   (oci-state-networks-requirement state)
+   invocations #:verbose? verbose?))
+
+(define* (oci-volumes-shepherd-service state runtime-state
+                                       #:key verbose?)
+  "Return a Shepherd service object that will create the volumes represented
+in STATE."
+  (define runtime-cli
+    (oci-runtime-state-runtime-cli runtime-state))
+  (define invocations
+    (map
+     (lambda (volume)
+       (oci-object-create-invocation
+        "volume" runtime-cli
+        (oci-volume-configuration-name volume)
+        (oci-volume-configuration->options volume)
+        (oci-runtime-state-runtime-extra-arguments runtime-state)
+        (oci-volume-configuration-extra-arguments volume)))
+     (oci-state-volumes state)))
+
+  (oci-object-shepherd-service
+   "volume" runtime-state (oci-state-volumes-name state)
+   (oci-state-volumes-requirement state)
+   invocations #:verbose? verbose?))
+
+(define (oci-service-accounts config)
+  (define user (oci-configuration-user config))
+  (define maybe-group (oci-configuration-group config))
+  (define runtime (oci-configuration-runtime config))
   (list (user-account
-         (name "oci-container")
+         (name user)
          (comment "OCI services account")
-         (group "docker")
-         (system? #t)
-         (home-directory "/var/empty")
+         (group "users")
+         (supplementary-groups
+          (list (oci-runtime-group runtime maybe-group)))
+         (system? (eq? 'docker runtime))
+         (home-directory (if (eq? 'podman runtime)
+                             (string-append "/home/" user)
+                             "/var/empty"))
+         (create-home-directory? (eq? 'podman runtime))
          (shell (file-append shadow "/sbin/nologin")))))
+
+(define* (oci-state->shepherd-services state runtime-state #:key verbose?)
+  "Returns a list of Shepherd services based on the input OCI state."
+  (define networks?
+    (> (length (oci-state-networks state)) 0))
+  (define volumes?
+    (> (length (oci-state-volumes state)) 0))
+  (append
+   (map
+    (lambda (c)
+      (oci-container-shepherd-service
+       state runtime-state c
+       #:verbose? verbose?
+       #:volumes? volumes?
+       #:networks? networks?))
+    (oci-state-containers state))
+   (if networks?
+       (list
+        (oci-networks-shepherd-service
+         state runtime-state
+         #:verbose? verbose?))
+       '())
+   (if volumes?
+       (list
+        (oci-volumes-shepherd-service
+         state runtime-state
+         #:verbose? verbose?))
+       '())))
+
+(define* (oci-configuration->oci-runtime-state config #:key verbose?)
+  (define runtime
+    (oci-configuration-runtime config))
+  (define home-service?
+    (oci-configuration-home-service? config))
+  (define runtime-cli
+    (if home-service?
+        (oci-runtime-home-cli config)
+        (oci-runtime-system-cli config)))
+  (define user
+    (if home-service?
+        #f
+        (oci-configuration-user config)))
+  (define group
+    (if home-service?
+        #f
+        (if (eq? runtime 'podman)
+            #~(group:name
+               (getgrgid
+                (passwd:gid
+                 (getpwnam #$user))))
+            (oci-runtime-group config (oci-configuration-group config)))))
+  (define runtime-requirement
+    (if home-service?
+        '()
+        (oci-runtime-system-requirement runtime)))
+  (define runtime-environment
+    (if home-service?
+        #~()
+        (oci-runtime-system-environment runtime user)))
+  (oci-runtime-state
+   (runtime runtime)
+   (runtime-cli runtime-cli)
+   (user user)
+   (group group)
+   (runtime-extra-arguments
+    (oci-configuration-runtime-extra-arguments config))
+   (runtime-environment runtime-environment)
+   (runtime-requirement runtime-requirement)))
+
+(define (oci-configuration->oci-state config)
+  (define runtime
+    (oci-configuration-runtime config))
+  (define home-service?
+    (oci-configuration-home-service? config))
+  (define networks-name
+    (if home-service?
+        (oci-networks-home-shepherd-name runtime)
+        (oci-networks-shepherd-name runtime)))
+  (define volumes-name
+    (if home-service?
+        (oci-volumes-home-shepherd-name runtime)
+        (oci-volumes-shepherd-name runtime)))
+  (define networks-requirement
+    (if home-service?
+        '()
+        '(networking)))
+  (oci-state
+   (containers (oci-configuration-containers config))
+   (networks (oci-configuration-networks config))
+   (volumes (oci-configuration-volumes config))
+   (networks-name networks-name)
+   (volumes-name volumes-name)
+   (networks-requirement networks-requirement)))
+
+(define (oci-configuration->shepherd-services config)
+  (let* ((verbose? (oci-configuration-verbose? config))
+         (state (oci-configuration->oci-state config))
+         (runtime-state
+          (oci-configuration->oci-runtime-state config #:verbose? verbose?)))
+    (oci-state->shepherd-services state runtime-state #:verbose? verbose?)))
+
+(define (oci-service-subids config)
+  "Return a subids-extension record representing subuids and subgids required by
+the rootless Podman backend."
+  (define (find-duplicates subids)
+    (let loop ((names '())
+               (subids subids))
+      (if (null? names)
+          names
+          (loop
+           (let ((name (subid-range-name (car subids))))
+             (if (member name names)
+                 (raise
+                  (formatted-message
+                   (G_ "Duplicated subid-range: ~a. subid-ranges names should be
+unique, please remove the duplicate.") name))
+                 (cons name names)))
+           (cdr subids)))))
+
+  (define runtime
+    (oci-configuration-runtime config))
+  (define user
+    (oci-configuration-user config))
+
+  (define subgids (oci-configuration-subgids-range config))
+  (find-duplicates subgids)
+
+  (define subuids (oci-configuration-subuids-range config))
+  (find-duplicates subgids)
+
+  (define container-users
+    (filter (lambda (range)
+              (and (maybe-value-set?
+                    (subid-range-name range))
+                   (not (string=? (subid-range-name range) user))))
+            (map (lambda (container)
+                   (subid-range
+                    (name
+                     (oci-container-configuration-user container))))
+                 (oci-configuration-containers config))))
+  (define subgid-ranges
+    (cons
+     (if (maybe-value-set? subgids)
+         subgids
+         (subid-range (name user)))
+     container-users))
+  (define subuid-ranges
+    (cons
+     (if (maybe-value-set? subuids)
+         subuids
+         (subid-range (name user)))
+     container-users))
+
+  (if (eq? 'podman runtime)
+      (subids-extension
+       (subgids
+        subgid-ranges)
+       (subuids
+        subuid-ranges))
+      (subids-extension)))
+
+(define (oci-objects-merge-lst a b object get-name)
+  (define (contains? value lst)
+    (member value (map get-name lst)))
+  (let loop ((merged '())
+             (lst (append a b)))
+    (if (null? lst)
+        merged
+        (loop
+         (let ((element (car lst)))
+           (when (contains? element merged)
+             (raise
+              (formatted-message
+               (G_ "Duplicated ~a: ~a. Names of ~a should be unique, please
+remove the duplicate.") object (get-name element) object)))
+           (cons element merged))
+         (cdr lst)))))
+
+(define (oci-extension-merge a b)
+  (oci-extension
+   (containers (oci-objects-merge-lst
+                (oci-extension-containers a)
+                (oci-extension-containers b)
+                "container"
+                (lambda (config)
+                  (define maybe-name
+                    (oci-container-configuration-provision config))
+                  (if (maybe-value-set? maybe-name)
+                      maybe-name
+                      (oci-image->container-name
+                       (oci-container-configuration-image config))))))
+   (networks (oci-objects-merge-lst
+              (oci-extension-networks a)
+              (oci-extension-networks b)
+              "network"
+              oci-network-configuration-name))
+   (volumes (oci-objects-merge-lst
+             (oci-extension-volumes a)
+             (oci-extension-volumes b)
+             "volume"
+             oci-volume-configuration-name))))
+
+(define (oci-service-profile runtime runtime-cli)
+  `(,bash-minimal
+    ,@(if (string? runtime-cli)
+          '()
+          (list
+           (cond
+            ((maybe-value-set? runtime-cli)
+             runtime-cli)
+            ((eq? 'podman runtime)
+             podman)
+            (else
+             docker-cli))))))
+
+(define (oci-configuration-extend config extension)
+  (oci-configuration
+   (inherit config)
+   (containers
+    (oci-objects-merge-lst
+     (oci-configuration-containers config)
+     (oci-extension-containers extension)
+     "container"
+     (lambda (oci-config)
+       (define runtime
+         (oci-configuration-runtime config))
+       (oci-container-shepherd-name runtime oci-config))))
+   (networks (oci-objects-merge-lst
+              (oci-configuration-networks config)
+              (oci-extension-networks extension)
+              "network"
+              oci-network-configuration-name))
+   (volumes (oci-objects-merge-lst
+             (oci-configuration-volumes config)
+             (oci-extension-volumes extension)
+             "volume"
+             oci-volume-configuration-name))))
+
+(define oci-service-type
+  (service-type
+   (name 'oci)
+   (extensions
+    (list
+     (service-extension profile-service-type
+                        (lambda (config)
+                          (let ((runtime-cli
+                                 (oci-configuration-runtime-cli config))
+                                (runtime
+                                 (oci-configuration-runtime config)))
+                            (oci-service-profile runtime runtime-cli))))
+     (service-extension subids-service-type
+                        oci-service-subids)
+     (service-extension account-service-type
+                        oci-service-accounts)
+     (service-extension shepherd-root-service-type
+                        oci-configuration->shepherd-services)))
+   ;; Concatenate OCI object lists.
+   (compose (lambda (args)
+              (fold oci-extension-merge
+                    (oci-extension)
+                    args)))
+   (extend oci-configuration-extend)
+   (default-value (oci-configuration))
+   (description
+    "This service implements the provisioning of OCI objects such
+as containers, networks and volumes.")))
diff --git a/gnu/services/docker.scm b/gnu/services/docker.scm
index 828ceea313a..6abfbc49a0b 100644
--- a/gnu/services/docker.scm
+++ b/gnu/services/docker.scm
@@ -31,7 +31,10 @@
   #:use-module (gnu system shadow)
   #:use-module (gnu packages docker)
   #:use-module (gnu packages linux)               ;singularity
+  #:use-module (guix deprecation)
+  #:use-module (guix diagnostics)
   #:use-module (guix gexp)
+  #:use-module (guix i18n)
   #:use-module (guix records)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 format)
@@ -67,16 +70,18 @@
                oci-container-configuration-volumes
                oci-container-configuration-container-user
                oci-container-configuration-workdir
-               oci-container-configuration-extra-arguments
-               oci-container-shepherd-service
-               %oci-container-accounts)
+               oci-container-configuration-extra-arguments)
 
   #:export (containerd-configuration
             containerd-service-type
             docker-configuration
             docker-service-type
             singularity-service-type
-            oci-container-service-type))
+            ;; For backwards compatibility, until the
+            ;; oci-container-service-type is fully deprecated.
+            oci-container-shepherd-service
+            oci-container-service-type
+            %oci-container-accounts))
 
 (define-maybe file-like)
 
@@ -297,17 +302,26 @@ bundles in Docker containers.")
 ;;; OCI container.
 ;;;
 
-(define (configs->shepherd-services configs)
-  (map oci-container-shepherd-service configs))
+;; For backwards compatibility, until the
+;; oci-container-service-type is fully deprecated.
+(define-deprecated (oci-container-shepherd-service config)
+  oci-service-type
+  ((@ (gnu services containers) oci-container-shepherd-service)
+   'docker config))
+(define %oci-container-accounts
+  (filter user-account? (oci-service-accounts (oci-configuration))))
 
 (define oci-container-service-type
   (service-type (name 'oci-container)
-                (extensions (list (service-extension profile-service-type
-                                                     (lambda _ (list docker-cli)))
-                                  (service-extension account-service-type
-                                                     (const %oci-container-accounts))
-                                  (service-extension shepherd-root-service-type
-                                                     configs->shepherd-services)))
+                (extensions
+                 (list (service-extension oci-service-type
+                                          (lambda (containers)
+                                            (warning
+                                             (G_
+                                              "'oci-container-service-type' is\
+ deprecated, use 'oci-service-type' instead~%"))
+                                            (oci-extension
+                                             (containers containers))))))
                 (default-value '())
                 (extend append)
                 (compose concatenate)