Buildah : Install2019/11/19

	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 sha256:729ec3a6ada3a6d26faca9b4779a037231f1762f759ef34c08bdd61bf52cd704
 68.21 MiB / 68.21 MiB  3s
Copying config sha256:0f3e07c0138fbe05abcb7a9cc7d63d9bd4c980c3f61fea5efa32e7c4217ef4da
 2.13 KiB / 2.13 KiB  0s
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
34f4b72375f6     *     f0858ad3febd docker.io/library/fedora:latest  fedora-working-container

# show container image list

[root@dlp ~]#

buildah images

REPOSITORY                        TAG      IMAGE ID       CREATED         SIZE
docker.io/library/fedora          latest   f0858ad3febd   2 weeks ago     201 MB

# possible to use images on podman

[root@dlp ~]#

podman images

REPOSITORY                        TAG      IMAGE ID       CREATED         SIZE
docker.io/library/fedora          latest   f0858ad3febd   2 weeks ago     201 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@dcd186abe47b /]#

dnf install python3

[root@dcd186abe47b /]#

exit

[root@dlp ~]#

buildah run $container whereis python3

python3: /usr/bin/python3 /usr/bin/python3.7 /usr/bin/python3.7m /usr/lib/python3.7 /usr/lib64/python3.7 /usr/include/python3.7m

[4]	Copy files into Working Container.

[root@dlp ~]#

echo "buildah test" > buildah.txt

[root@dlp ~]#

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

a92cc66fa2673f2db0e3ae43cb5e7aaa4dffcfc4116b7a1f2531f2421571fd77

[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/3167d596569a00e8e6cc6832161238a5524453bd619400c790ce4097b2ed38fe/merged

[root@dlp ~]#

ll /var/lib/containers/storage/overlay/3167d596569a00e8e6cc6832161238a5524453bd619400c790ce4097b2ed38fe/merged

total 0
lrwxrwxrwx.  1 root root   7 Jul 25 09:35 bin -> usr/bin
dr-xr-xr-x.  2 root root   6 Jul 25 09:35 boot
drwxr-xr-x.  2 root root   6 Oct 28 14:47 dev
drwxr-xr-x.  1 root root  38 Oct 28 14:48 etc
.....
.....

# unmount

[root@dlp ~]#

buildah umount $container

dcd186abe47b5dda92a72cabfc8dd4e59bbf6c9e43eed770265313618d8271fe

[6]	Create a container image from Working Container.

[root@dlp ~]#

buildah commit $container my-fedora:latest

Getting image source signatures
Copying blob 2ae3cee18c8e skipped: already exists
Copying blob e2f90fd5fd71 done
Copying config c0eb1c2287 done
Writing manifest to image destination
Storing signatures
c0eb1c22870581816ccac863a96578f918ced48b497c49b0ff5e8c2c674dd01a

[root@dlp ~]#

buildah images

REPOSITORY                        TAG      IMAGE ID       CREATED          SIZE
localhost/my-fedora               latest   c0eb1c228705   34 seconds ago   592 MB
docker.io/library/fedora          latest   f0858ad3febd   2 weeks ago      201 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   c0eb1c228705   6 minutes ago   592 MBdocker.io/library/fedora          latest   f0858ad3febd   2 weeks ago     201 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 sha256:9e607bb861a7d58bece26dd2c02874beedd6a097c1b6eca5255d5eb0d2236983
 216.91 MiB / 216.91 MiB  21s
Copying blob sha256:6827f6da87706c243a81476c7a110af0367c7f8ca91396b8ffb782c9edd3c5a8
 34.12 MiB / 34.12 MiB  4s
Copying config sha256:0a3ba69587a4cc6abdcc951a8fe2ca4a63745263cac2b4bfcaa1e146c8730fff
 1.20 KiB / 1.20 KiB  0s
Writing manifest to image destination
Storing signatures
Successfully pushed //node01.srv.world:5000/my-fedora:latest@sha256:9384a0326fc7e68c628f84f4cd8443858dd85d782efba6b7b82fe0e9e1d85b87

[root@dlp ~]#

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

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

# 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        f32a97de94e1   7 months ago     26.4 MB

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