Buildah : Install2020/05/11

	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 [fedora] image

[root@dlp ~]#

buildah from fedora

Getting image source signatures
Copying blob 3088721d7dbf0.0b / 0.0b
Copying config d81c91deec done
Writing manifest to image destination
Storing signatures
fedora-working-container

# show container list

[root@dlp ~]#

buildah containers

CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
3b142346cd14     *     d81c91deec0d registry.fedoraproject.org/fe... fedora-working-container

# show container image list

[root@dlp ~]#

buildah images

REPOSITORY                          TAG      IMAGE ID       CREATED       SIZE
registry.fedoraproject.org/fedora   latest   d81c91deec0d   11 days ago   208 MB

# possible to use images on podman

[root@dlp ~]#

podman images

REPOSITORY                          TAG      IMAGE ID       CREATED       SIZE
registry.fedoraproject.org/fedora   latest   d81c91deec0d   11 days ago   208 MB

[3]	Operate Working Container.

# set shell variable

[root@dlp ~]#

container=$(buildah from fedora)

[root@dlp ~]#

echo $container

fedora-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@0ffef2df688f /]#

dnf install python3

[root@0ffef2df688f /]#

exit

[root@dlp ~]#

buildah run $container whereis python3

python3: /usr/bin/python3 /usr/bin/python3.8 /usr/lib/python3.8 /usr/lib64/python3.8 /usr/include/python3.8

[4]	Copy files into Working Container.

[root@dlp ~]#

echo "buildah test" > buildah.txt

[root@dlp ~]#

buildah copy $container buildah.txt /tmp/buildah.txt

c1172b94183d8ad1541c3d96e54e11a21c6b8508a0ead5d8b902b2e035ba6372

[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/525ee63daa36f2b9d04d4e21ec16091c91c0ccad1f87fa2bfb1583afd70abd48/merged

[root@dlp ~]#

ll /var/lib/containers/storage/overlay/525ee63daa36f2b9d04d4e21ec16091c91c0ccad1f87fa2bfb1583afd70abd48/merged

total 0
lrwxrwxrwx.  1 root root   7 Jan 28 13:30 bin -> usr/bin
dr-xr-xr-x.  2 root root   6 Jan 28 13:30 boot
drwxr-xr-x.  2 root root   6 Apr 29 02:47 dev
drwxr-xr-x.  1 root root  38 Apr 29 02:47 etc
drwxr-xr-x.  2 root root   6 Jan 28 13:30 home
.....
.....

# unmount

[root@dlp ~]#

buildah umount $container

0ffef2df688fb628c7fcfaf61a0f8962f2a44abf82112ff413b51f5b9d788b2c

[6]	Create a container image from Working Container.

[root@dlp ~]#

buildah commit $container my-fedora:latest

Getting image source signatures
Copying blob a4c0fa2b217d skipped: already exists
Copying blob c5baae57ea51 done
Copying config c3e6a732a5 done
Writing manifest to image destination
Storing signatures
c3e6a732a5c5577d6999b3b564c3d0811f09601afd998f78298ae721d8d12908

[root@dlp ~]#

buildah images

REPOSITORY                          TAG      IMAGE ID       CREATED          SIZE
localhost/my-fedora                 latest   c3e6a732a5c5   21 seconds ago   392 MB
registry.fedoraproject.org/fedora   latest   d81c91deec0d   11 days ago      208 MB

# possible tp use container images on podman

[root@dlp ~]#

podman run localhost/my-fedora echo my fedora

my fedora

[7]	Push a container image to specified Registry.

[root@dlp ~]#

buildah images

REPOSITORY                          TAG      IMAGE ID       CREATED          SIZE
localhost/my-fedora                 latest   c3e6a732a5c5   48 seconds ago   392 MB
registry.fedoraproject.org/fedora   latest   d81c91deec0d   11 days ago      208 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-fedora node01.srv.world:5000/my-fedora

Getting image source signatures
Copying blob c5baae57ea51 done
Copying blob a4c0fa2b217d done
Copying config c3e6a732a5 done
Writing manifest to image destination
Storing signatures

[root@dlp ~]#

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

{"repositories":["my-fedora","nginx_server"]}

# possible to Pull from other nodes

[root@node01 ~]#

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

[root@node01 ~]#

podman images

REPOSITORY                        TAG      IMAGE ID       CREATED          SIZE
node01.srv.world:5000/my-fedora   latest   0a3ba69587a4   19 minutes ago   263 MB
docker.io/library/registry          2        708bc6af7e5e   3 months ago   26.3 MB

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