Podman support

README.md

@@ -1,10 +1,11 @@
 # xcp-ng-build-env
 
-This docker config and collection of supporting scripts allows for creating
-a docker container to work on and build a XCP-ng package from an SRPM or from
-a directory containing a `SOURCES/` and a `SPECS/` directory along with appropriate
-RPM spec file and software sources.
-It will build a Docker container with the right build environment (including some
+This container config and collection of supporting scripts allows for
+creating a container to work on and build a XCP-ng package from an
+SRPM or from a directory containing a `SOURCES/` and a `SPECS/`
+directory along with appropriate RPM spec file and software sources.
+
+It will build a container with the right build environment (including some
 useful tools).
 Depending on the parameters, it will either do everything automatically to build a
 given package, or just install build-dependencies and let you work manually from a shell
@@ -13,14 +14,21 @@ want.
 
 ## Configuration
 
-You'll need to install docker. Follow the instructions for your platform on
-https://www.docker.com/
+You'll need to install docker or podman. Podman should be available
+from your distro repositories, for Docker follow the instructions for
+your platform on https://www.docker.com/
+
+If you have both installed, docker will be used by default.  If you
+want to use a specific container runtime, set `XCPNG_OCI_RUNNER` to
+the docker-compatible command to use (typically `podman` or `docker`).
 
-## Building the docker image(s)
+## Building the container image(s)
 
-You need one docker image per target version of XCP-ng.
+You need one container image per target version of XCP-ng.
 
-Clone this repository (outside any docker container), then use `build.sh` to generate the docker images for the wanted releases of XCP-ng.
+Clone this repository (outside any container), then use `build.sh` to
+generate the images for the wanted releases of XCP-ng.
+Note that Docker and Podman store container images separately.
 
 ```
 Usage: ./build.sh {version_of_XCP_ng}
@@ -115,7 +123,7 @@ git clone https://github.com/xcp-ng-rpms/xapi.git
 
 * `-b` / `--branch` allows to select which version of XCP-ng to work on (defaults to the latest known version if not specified).
 * `--no-exit` drops you to a shell after the build, instead of closing the container. Useful if the build fails and you need to debug.
-* `--rm` destroys the container on exit. Helps preventing docker from using too much space on disk. You can still reclaim space afterwards by running `docker container prune` and `docker image prune`
+* `--rm` destroys the container on exit. Helps preventing containers from using too much space on disk. You can still reclaim space afterwards by running `docker container prune` and `docker image prune`
 * `-v` / `--volume` (see *Mounting repos from outside the container* below)
 
 
@@ -149,9 +157,7 @@ make
 
 If you'd like to develop using the tools on your host and preserve the changes
 to source and revision control but still use the container for building, you
-can do using by using a docker volume.
-
-Once you have built your image you can run it with an extra argument to mount
+can do using by mouning a volume in the container, using the `-v` option to mount
 a directory from your host to a suitable point inside the container. For
 example, if I clone some repos into a directory on my host, say `/work/code/`,
 then I can mount it inside the container as follows:

build.sh

@@ -8,6 +8,23 @@ if [ -z "$1" ]; then
     exit
 fi
 
+RUNNER=""
+if [ -n "$XCPNG_OCI_RUNNER" ]; then
+    RUNNER="$XCPNG_OCI_RUNNER"
+else
+    SUPPORTED_RUNNERS="docker podman"
+    for COMMAND in $SUPPORTED_RUNNERS; do
+        if command -v $COMMAND >/dev/null; then
+            RUNNER="$COMMAND"
+            break
+        fi
+    done
+    if [ -z "$RUNNER" ]; then
+        echo >&2 "cannot find a supported runner: $SUPPORTED_RUNNERS"
+        exit 1
+    fi
+fi
+
 cd $(dirname "$0")
 
 CUSTOM_ARGS=()
@@ -56,7 +73,7 @@ fi
 CUSTOM_ARGS+=( "--build-arg" "CUSTOM_BUILDER_UID=${CUSTOM_UID}" )
 CUSTOM_ARGS+=( "--build-arg" "CUSTOM_BUILDER_GID=${CUSTOM_GID}" )
 
-docker build \
+"$RUNNER" build \
     "${CUSTOM_ARGS[@]}" \
     -t xcp-ng/xcp-ng-build-env:${1} \
     --ulimit nofile=1024 \

run.py

@@ -1,7 +1,11 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-""" Thin wrapper around "docker run" which simplifies the creation of a build environment for XCP-ng packages. """
+"""
+Thin wrapper around "docker run" or "podman run".
+
+Simplifies the creation of a build environment for XCP-ng packages.
+"""
 
 import argparse
 import os
@@ -16,6 +20,16 @@
 DEFAULT_BRANCH = '8.3'
 DEFAULT_ULIMIT_NOFILE = 1024
 
+RUNNER = os.getenv("XCPNG_OCI_RUNNER")
+if RUNNER is None:
+    SUPPORTED_RUNNERS = "docker podman"
+    for command in SUPPORTED_RUNNERS.split():
+        if shutil.which(command):
+            RUNNER = command
+            break
+    else:
+        raise Exception(f"cannot find a supported runner: {SUPPORTED_RUNNERS}")
+
 def make_mount_dir():
     """ Make a randomly-named directory under SRPMS_MOUNT_ROOT. """
     srpm_mount_dir = os.path.join(SRPMS_MOUNT_ROOT, str(uuid.uuid4()))
@@ -32,6 +46,12 @@ def copy_srpms(srpm_mount_dir, srpms):
         srpm_name = os.path.basename(srpm)
         shutil.copyfile(srpm, os.path.join(srpm_mount_dir, srpm_name))
 
+def is_podman(runner):
+    if os.path.basename(runner) == "podman":
+        return True
+    if subprocess.getoutput(f"{runner} --version").startswith("podman "):
+        return True
+    return False
 
 def main():
     """ Main entry point. """
@@ -93,7 +113,9 @@ def main():
 
     args = parser.parse_args(sys.argv[1:])
 
-    docker_args = ["docker", "run", "-i", "-t", "-u", "builder"]
+    docker_args = [RUNNER, "run", "-i", "-t", "-u", "builder"]
+    if is_podman(RUNNER):
+        docker_args += ["--userns=keep-id"]
     if os.uname()[4] != "x86_64":
         docker_args += ["--platform", "linux/amd64"]
     if args.rm: