Question

我想将podman作为运行CI / CD管道的容器运行。但是，我不断从podman容器中收到此错误：

$ podman info
ERRO[0000] 'overlay' is not supported over overlayfs
Error: could not get runtime: 'overlay' is not supported over overlayfs: backing file system is unsupported for this graph driver

我正在使用Jenkins Kubernetes plugin来编写在Kubernetes集群中作为容器运行的CI / CD管道。我已经成功编写了使用Docker-in-Docker容器运行docker build和docker push命令的管道。

但是，在容器中运行Docker客户端和Docker Daemon会使CI / CD环境非常膨胀，难以配置，并且不适合使用。因此，我认为我可以使用podman从Dockerfiles构建Docker映像，而无需使用胖Docker守护进程。

问题在于 podman 太新了，以至于我以前从未见过有人尝试过这样做，也没有足够的podman专家来正确执行此操作。

因此，使用podman installation instructions for Ubuntu创建了以下Dockerfile：

FROM ubuntu:16.04

RUN apt-get update -qq \
    && apt-get install -qq -y software-properties-common uidmap \
    && add-apt-repository -y ppa:projectatomic/ppa \
    && apt-get update -qq \
    && apt-get -qq -y install podman

# To keep it running
CMD tail -f /dev/null

所以我构建了图像并按如下所示运行它：

# Build
docker build -t podman:ubuntu-16.04 .

# Run
docker run --name podman -d podman:ubuntu-16.04

然后在正在运行的容器上运行此命令时，出现错误：

$ docker exec -ti podman bash -c "podman info"

ERRO[0000] 'overlay' is not supported over overlayfs
Error: could not get runtime: 'overlay' is not supported over overlayfs: backing file system is unsupported for this graph driver

我在装有Ubuntu 16.04的计算机上安装了podman，并运行了相同的podman info命令，得到了预期的结果：

host:
  BuildahVersion: 1.8-dev
  Conmon:
    package: 'conmon: /usr/libexec/crio/conmon'
    path: /usr/libexec/crio/conmon
    version: 'conmon version , commit: '
  Distribution:
    distribution: ubuntu
    version: "16.04"
  MemFree: 2275770368
  MemTotal: 4142137344
  OCIRuntime:
    package: 'cri-o-runc: /usr/lib/cri-o-runc/sbin/runc'
    path: /usr/lib/cri-o-runc/sbin/runc
    version: 'runc version spec: 1.0.1-dev'
  SwapFree: 2146758656
  SwapTotal: 2146758656
  arch: amd64
  cpus: 2
  hostname: jumpbox-4b3620b3
  kernel: 4.4.0-141-generic
  os: linux
  rootless: false
  uptime: 222h 46m 33.48s (Approximately 9.25 days)
insecure registries:
  registries: []
registries:
  registries:
  - docker.io
store:
  ConfigFile: /etc/containers/storage.conf
  ContainerStore:
    number: 0
  GraphDriverName: overlay
  GraphOptions: null
  GraphRoot: /var/lib/containers/storage
  GraphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  ImageStore:
    number: 15
  RunRoot: /var/run/containers/storage
  VolumePath: /var/lib/containers/storage/volumes

有人知道我该如何解决该错误并使podman从容器中工作？

Answer 1

您的Dockerfile也应该安装iptables：

FROM ubuntu:16.04

RUN apt-get update -qq \
    && apt-get install -qq -y software-properties-common uidmap \
    && add-apt-repository -y ppa:projectatomic/ppa \
    && apt-get update -qq \
    && apt-get -qq -y install podman \
    && apt-get install -y iptables

# To keep it running
CMD tail -f /dev/null

然后使用以下命令运行命令：

docker run -ti --rm podman:test bash -c "podman --storage-driver=vfs info"

这应该给您期望的答复。

Answer 2

我自己尝试了一个更宽松的配置（--privileged=true），从主机挂载了存储卷，并且在容器中安装了iptables并能够运行它（即{{1 }}。

sudo apt-get install iptables

如果您想使用$ podman run -it --rm -v /var/run/containers/storage:/var/run/containers/storage -v /var/lib/containers/storage:/var/lib/containers/storage --storage-driver=overlay --privileged=true mine bash root@e275668d7c36:/# apt-get install -y -qq iptables ... root@e275668d7c36:/# podman info host: BuildahVersion: 1.8-dev Conmon: package: 'conmon: /usr/libexec/crio/conmon' path: /usr/libexec/crio/conmon version: 'conmon version , commit: ' Distribution: distribution: ubuntu version: "16.04" MemFree: 71659520 MemTotal: 482099200 OCIRuntime: package: 'cri-o-runc: /usr/lib/cri-o-runc/sbin/runc' path: /usr/lib/cri-o-runc/sbin/runc version: 'runc version spec: 1.0.1-dev' SwapFree: 0 SwapTotal: 0 arch: amd64 cpus: 2 hostname: e275668d7c36 kernel: 4.15.0-1035-aws os: linux rootless: false uptime: 315h 17m 53s (Approximately 13.12 days) insecure registries: registries: [] registries: registries: [] store: ConfigFile: /etc/containers/storage.conf ContainerStore: number: 2 GraphDriverName: overlay GraphOptions: null GraphRoot: /var/lib/containers/storage GraphStatus: Backing Filesystem: extfs Native Overlay Diff: "true" Supports d_type: "true" Using metacopy: "false" ImageStore: number: 4 RunRoot: /var/run/containers/storage VolumePath: /var/lib/containers/storage/volumes，也可以使用--privileged标志。

请记住，还有其他一些专门用于构建容器的工具，其中一些没有特权模式：

Kaniko
img
Buildkit
Buildah（与Podman配套）
Bazel（带有container构建模块）
Knative container build templates

Answer 3

mihai的建议在info上获得了成功，但是例如，我尝试run --rm docker.io/library/hello-world时就遇到了错误：

error creating network namespace for container …: mount --make-rshared /var/run/netns failed: "operation not permitted"
failed to mount shm tmpfs "/var/lib/containers/storage/vfs-containers/…/userdata/shm": operation not permitted

我只能通过为映像设置非root用户然后在特权模式下运行容器来解决此问题，这违背了练习的目的，因为DinD已经可以做到这一点：

FROM ubuntu:18.04

RUN apt-get update -qq \
    && apt-get install -qq -y software-properties-common uidmap \
    && add-apt-repository -y ppa:projectatomic/ppa \
    && apt-get update -qq \
    && apt-get -qq -y install podman \
    && apt-get install -y iptables

RUN adduser --disabled-login --gecos test test

USER test

ENTRYPOINT ["podman", "--storage-driver=vfs"]
CMD ["info"]

用作

docker build -t podman:test .
docker run --rm --privileged podman:test run --rm docker.io/library/hello-world

如何从容器内部运行podman？

3 个答案: