CentOS Stream 10
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Buildah : Install2025/01/20
 

Install Buildah that supports to create Container images.

It's possible to create OCI (Open Container Initiative) format image without specific Service Daemon.

[1] Install Buildah.
[root@dlp ~]#
dnf -y install buildah
[2] This is the basic usage for Buildah.
Create a working container from an image.
# create a working container from [centos] image

[root@dlp ~]#
buildah from centos:stream10 

Resolved "centos" as an alias (/etc/containers/registries.conf.d/000-shortnames.conf)
Trying to pull quay.io/centos/centos:stream10...
Getting image source signatures
Copying blob efdebfb97295 done   |
Copying config 1ef274445e done   |
Writing manifest to image destination
centos-working-container
# show container list

[root@dlp ~]#
buildah containers 

CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
26b34e5e7a96     *     1ef274445e32 quay.io/centos/centos:stream10   centos-working-container
# show container image list

[root@dlp ~]#
buildah images 

REPOSITORY              TAG        IMAGE ID       CREATED      SIZE
quay.io/centos/centos   stream10   1ef274445e32   6 days ago   311 MB
# possible to use images on podman

[root@dlp ~]#
podman images 

REPOSITORY             TAG         IMAGE ID      CREATED     SIZE
quay.io/centos/centos  stream10    1ef274445e32  6 days ago  311 MB
[3] Operate Working Container.
# set shell variable

[root@dlp ~]#
container=$(buildah from centos:stream10)

[root@dlp ~]#
echo $container

centos-working-container-1
# possible to run commands

[root@dlp ~]#
buildah run $container echo "Hello Buildah World"

Hello Buildah World
[root@dlp ~]#
buildah run $container bash

[root@ade3a026557e /]#
dnf -y install python3

[root@ade3a026557e /]#
exit

[root@dlp ~]#
buildah run $container python3 -V

Python 3.12.8
[4] Copy files into Working Container.
[root@dlp ~]#
echo "buildah test" > buildah.txt

[root@dlp ~]#
buildah copy $container buildah.txt /tmp/buildah.txt 

7553c62d21edda64a3067fa9805a5cd8e5781c6058be12eb9792d7e0e9781ed4
[root@dlp ~]#
buildah run $container cat /tmp/buildah.txt

buildah test
[5] Mount filesystem of Working Container.
[root@dlp ~]#
buildah mount $container 

/var/lib/containers/storage/overlay/9c82f3c99ed1d030a9cfea5a564a3f3be77bc9494c7e4b1fdc48151d0427700d/merged
[root@dlp ~]#
ll /var/lib/containers/storage/overlay/9c82f3c99ed1d030a9cfea5a564a3f3be77bc9494c7e4b1fdc48151d0427700d/merged 

total 4
dr-xr-xr-x.  2 root root    6 Oct 29 09:00 afs
lrwxrwxrwx.  1 root root    7 Oct 29 09:00 bin -> usr/bin
dr-xr-xr-x.  2 root root    6 Oct 29 09:00 boot
drwxr-xr-x.  2 root root    6 Jan 13 13:29 dev
drwxr-xr-x. 46 root root 4096 Jan 13 13:30 etc
drwxr-xr-x.  2 root root    6 Oct 29 09:00 home
.....
.....
# unmount

[root@dlp ~]#
buildah umount $container 

ade3a026557e2424929aa03f5fd23e9120f995549f7284c89f18f4c4a7f46d76
[6] Create a container image from Working Container.
[root@dlp ~]#
buildah commit $container my-centos:latest 

Getting image source signatures
Copying blob 37e999dd80a5 skipped: already exists
Copying blob 0fa7f58369bd done   |
Copying config 5a02d770e9 done   |
Writing manifest to image destination
5a02d770e9eadb5f89edb768188105c6615dcf24b1405d8764ceea459fa6b8ec
[root@dlp ~]#
buildah images 

REPOSITORY              TAG        IMAGE ID       CREATED          SIZE
localhost/my-centos     latest     5a02d770e9ea   16 seconds ago   329 MB
quay.io/centos/centos   stream10   1ef274445e32   6 days ago       311 MB
# possible to use container images on podman

[root@dlp ~]#
podman run localhost/my-centos uname -a

Linux bdd95d1b155a 6.12.0-39.el10.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Jan 9 16:11:58 UTC 2025 x86_64 GNU/Linux
[7] Push a container image to a specified Registry.
[root@dlp ~]#
buildah images 

REPOSITORY              TAG        IMAGE ID       CREATED              SIZE
localhost/my-centos     latest     5a02d770e9ea   About a minute ago   329 MB
quay.io/centos/centos   stream10   1ef274445e32   6 days ago           311 MB
# push [localhost/my-centos] image to [node01.srv.world:5000] registry
# if target registry is not on SSL/TLS, need [--tls-verify=false] option

[root@dlp ~]#
buildah push --tls-verify=false localhost/my-centos node01.srv.world:5000/my-centos 

Getting image source signatures
Copying blob 37e999dd80a5 done   |
Copying blob 0fa7f58369bd done   |
Copying config 5a02d770e9 done   |
Writing manifest to image destination
[root@dlp ~]#
curl node01.srv.world:5000/v2/_catalog

{"repositories":["my-centos"]}
# possible to Pull from other nodes

[root@node01 ~]#
podman pull --tls-verify=false node01.srv.world:5000/my-centos

[root@node01 ~]#
podman images 

REPOSITORY                       TAG         IMAGE ID      CREATED        SIZE
node01.srv.world:5000/my-centos  latest      5a02d770e9ea  6 minutes ago  329 MB
docker.io/library/registry       2           282bd1664cf1  15 months ago  26 MB
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