github.com/hanks177/podman/v4@v4.1.3-0.20220613032544-16d90015bc83/contrib/hello/README.md (about)

     1  ![PODMAN logo](../../logo/podman-logo-source.svg)
     2  
     3  # Podman Hello World image
     4  
     5  ## Overview
     6  
     7  This directory contains the Containerfile and bash script necessary to create the
     8  "hello" podman image housed on quay.io under the Podman account in a public
     9  repository.  The image is public and can be pulled without credentials.
    10  
    11  Using this image is helpful to:
    12  
    13   * Prove that basic Podman operations are working on the host.
    14   * Shows that the image was pulled from the quay.io container registry.
    15   * Container creation was successfully accomplished. (`podman ps -a`)
    16   * The created container was able to stream output to your terminal.
    17  
    18  ## Directory Contents
    19  
    20  The contents of this directory contain:
    21   * ./Containerfile
    22   * ./podman_hello_world.c
    23  
    24  ## Sample Usage
    25  
    26  To simply run the image:
    27  
    28  ```
    29  podman run quay.io/podman/hello
    30  
    31  !... Hello Podman World ...!
    32  
    33           .--"--.
    34         / -     - \
    35        / (O)   (O) \
    36     ~~~| -=(,Y,)=- |
    37      .---. /`  \   |~~
    38   ~/  o  o \~~~~.----. ~~
    39    | =(X)= |~  / (O (O) \
    40     ~~~~~~~  ~| =(Y_)=-  |
    41    ~~~~    ~~~|   U      |~~
    42  
    43  Project:   https://github.com/containers/podman
    44  Website:   https://podman.io
    45  Documents: https://docs.podman.io
    46  Twitter:   @Podman_io
    47  ```
    48  To build the image yourself, copy the files from this directory into
    49  a local directory and issue these commands:
    50  
    51  ```
    52  podman build -t myhello .
    53  podman run myhello
    54  ```
    55  
    56  ## Potential Issues:
    57  
    58  The image runs as a rootless user with the UID set to `1000`.
    59  If the /etc/subuid and /etch/subgid values are not set appropriately to run as a
    60  rootless user on the host, an error like this might be raised:
    61  
    62  ```
    63  Copying blob acab339ca1e8 done
    64  ERRO[0002] Error while applying layer: ApplyLayer exit status 1 stdout:  stderr: potentially insufficient UIDs or GIDs available in user namespace (requested 0:12 for /var/spool/mail): Check /etc/subuid and /etc/subgid: lchown /var/spool/mail: invalid argument
    65  Error: writing blob: adding layer with blob "sha256:ee0cde9de8a68f171a8c03b0e9954abf18576947e2f3187e84d8c31ccd8f6a09": ApplyLayer exit status 1 stdout:  stderr: potentially insufficient UIDs or GIDs available in user namespace (requested 0:12 for /var/spool/mail): Check /etc/subuid and /etc/subgid: lchown /var/spool/mail: invalid argument
    66  ```
    67  
    68  Please refer to this [blog post](https://www.redhat.com/sysadmin/rootless-podman) for further configuration information.
    69  
    70  ## THANKS!
    71  
    72  Many Thanks to @afbjorklund for a great discussion during the
    73  first revision of this container image that resulted in moving
    74  from using bash to using C, and the ensuing changes to the
    75  Containerfile.
    76  
    77  Also many thanks to @mairin for the awesome ASCII art!