Buildah : Install2021/07/30

	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 [rockylinux] image

[root@dlp ~]#

buildah from docker.io/rockylinux/rockylinux

rockylinux-working-container

# show container list

[root@dlp ~]#

buildah containers

CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
28ae0a676f16     *     333da17614b6 docker.io/rockylinux/rockylin... rockylinux-working-container

# show container image list

[root@dlp ~]#

buildah images

REPOSITORY                        TAG      IMAGE ID       CREATED       SIZE
docker.io/rockylinux/rockylinux   latest   333da17614b6   5 weeks ago   234 MB

# possible to use images on podman

[root@dlp ~]#

podman images

REPOSITORY                       TAG     IMAGE ID      CREATED      SIZE
docker.io/rockylinux/rockylinux  latest  333da17614b6  5 weeks ago  234 MB

[3]	Operate Working Container.

# set shell variable

[root@dlp ~]#

container=$(buildah from docker.io/rockylinux/rockylinux)

[root@dlp ~]#

echo $container

rockylinux-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@2dc9c34b8aa8 /]#

dnf -y install python36

[root@2dc9c34b8aa8 /]#

exit

[root@dlp ~]#

buildah run $container whereis python3

python3: /usr/bin/python3.6 /usr/bin/python3.6m /usr/bin/python3 /usr/lib/python3.6 /usr/lib64/python3.6 /usr/include/python3.6m /usr/share/man/man1/python3.1.gz

[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/b41bf5383e934a538c540c9e86b1628568c601a62d7a1c5c99637c5b0a6cf59c/merged

[root@dlp ~]#

ll /var/lib/containers/storage/overlay/b41bf5383e934a538c540c9e86b1628568c601a62d7a1c5c99637c5b0a6cf59c/merged

total 0
lrwxrwxrwx. 1 root root  7 Mar 15 04:28 bin -> usr/bin
drwxr-xr-x. 2 root root  6 Jun 21 14:03 dev
drwxr-xr-x. 1 root root 56 Jul 30 10:34 etc
drwxr-xr-x. 2 root root  6 Mar 15 04:28 home
.....
.....

[root@dlp ~]#

buildah umount $container

2dc9c34b8aa8f63741fc575164544181b64d68e8ba81651a37b2b11b54cb96ce

[6]	Create a container image from Working Container.

[root@dlp ~]#

buildah commit $container my-rockylinux:latest

Getting image source signatures
...
...
...
Writing manifest to image destination
Storing signatures
5820cb7173a9583e4f676009d182a5b807f89322e4c31d3c743aeb501601eac6

[root@dlp ~]#

buildah images

REPOSITORY                        TAG      IMAGE ID       CREATED          SIZE
localhost/my-rockylinux           latest   5820cb7173a9   19 seconds ago   282 MB
docker.io/rockylinux/rockylinux   latest   333da17614b6   5 weeks ago      234 MB

# possible to use container images on podman

[root@dlp ~]#

podman run localhost/my-rockylinux hostname

35862422dc0a

[7]	Push a container image to specified Registry.

[root@dlp ~]#

buildah images

REPOSITORY                        TAG      IMAGE ID       CREATED          SIZE
localhost/my-rockylinux           latest   5820cb7173a9   47 seconds ago   282 MB
docker.io/rockylinux/rockylinux   latest   333da17614b6   5 weeks ago      234 MB

# push [localhost/my-rockylinux] 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-rockylinux node01.srv.world:5000/my-rockylinux

Getting image source signatures
...
...
...
Writing manifest to image destination
Storing signatures

[root@dlp ~]#

curl node01.srv.world:5000/v2/_catalog

{"repositories":["my-rockylinux"]}

# possible to Pull from other nodes

[root@node01 ~]#

podman pull --tls-verify=false node01.srv.world:5000/my-rockylinux

[root@node01 ~]#

podman images

REPOSITORY                           TAG     IMAGE ID      CREATED        SIZE
node01.srv.world:5000/my-rockylinux  latest  5820cb7173a9  7 minutes ago  282 MB
docker.io/library/registry           2       1fd8e1b0bb7e  3 months ago   26.8 MB

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