mirror of https://github.com/containers/podman.git
78 lines
2.6 KiB
Markdown
78 lines
2.6 KiB
Markdown
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# Podman Hello World image
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## Overview
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This directory contains the Containerfile and bash script necessary to create the
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"hello" podman image housed on quay.io under the Podman account in a public
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repository. The image is public and can be pulled without credentials.
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Using this image is helpful to:
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* Prove that basic Podman operations are working on the host.
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* Shows that the image was pulled from the quay.io container registry.
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* Container creation was successfully accomplished. (`podman ps -a`)
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* The created container was able to stream output to your terminal.
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## Directory Contents
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The contents of this directory contain:
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* ./Containerfile
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* ./podman_hello_world.c
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## Sample Usage
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To simply run the image:
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```
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podman run quay.io/podman/hello
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!... Hello Podman World ...!
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.--"--.
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/ - - \
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/ (O) (O) \
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~~~| -=(,Y,)=- |
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.---. /` \ |~~
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~/ o o \~~~~.----. ~~
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| =(X)= |~ / (O (O) \
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~~~~~~~ ~| =(Y_)=- |
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~~~~ ~~~| U |~~
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Project: https://github.com/containers/podman
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Website: https://podman.io
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Documents: https://docs.podman.io
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Twitter: @Podman_io
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```
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To build the image yourself, copy the files from this directory into
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a local directory and issue these commands:
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```
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podman build -t myhello .
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podman run myhello
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```
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## Potential Issues:
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The image runs as a rootless user with the UID set to `1000`.
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If the /etc/subuid and /etch/subgid values are not set appropriately to run as a
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rootless user on the host, an error like this might be raised:
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```
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Copying blob acab339ca1e8 done
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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
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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
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```
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Please refer to this [blog post](https://www.redhat.com/sysadmin/rootless-podman) for further configuration information.
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## THANKS!
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Many Thanks to @afbjorklund for a great discussion during the
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first revision of this container image that resulted in moving
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from using bash to using C, and the ensuing changes to the
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Containerfile.
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Also many thanks to @mairin for the awesome ASCII art!
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