TripleO Modify Image

A role to allow modification to container images built for the TripleO project.

Role Variables

Variables used for modify image

Name	Default Value	Description
source_image	[undefined]	Mandatory fully qualified reference to the source image to be modified. The supplied Dockerfile will be copied and modified to make the FROM directive match this variable.
modify_dir_path	[undefined]	Mandatory path to the directory containing the Dockerfile to modify the image
modified_append_tag	date +-modified-%Y%m%d%H%M%S	String to be appended after the tag to indicate this is a modified version of the source image.
target_image	[undefined]	If set, the modified image will be tagged with target_image + modified_append_tag. If target_image is not set, the modified image will be tagged with source_image + modified_append_tag. If the purpose of the image is not changing, it may be enough to rely on the source_image + modified_append_tag tag to identify that this is a modified version of the source image.

Variables used for yum update

Name	Default Value	Description
source_image	[undefined]	See modify image variables
modified_append_tag	date +-modified-%Y%m%d%H%M%S	See modify image variables
target_image	''	See modify image variables
rpms_path	''	If set, packages present in rpms_path will be updated but dependencies must also be included if required as yum is called with localupdate.
update_repo	''	If set, packages from this repo will be updated. Other repos will only be used for dependencies of these updates.
yum_repos_dir_path	None	Optional path of directory to be used as /etc/yum.repos.d during the update
yum_cache	None	Optional path to the host directory for yum cache during the update. Requires an overlay-enabled FS that also supports SE context relabling.
force_purge_yum_cache	False	Optional argument that tells buildah to forcefully re-populate the yum cache with new contents.

Variables used for yum install

Name	Default Value	Description
source_image	[undefined]	See modify image variables
modified_append_tag	date +-modified-%Y%m%d%H%M%S	See modify image variables
target_image	''	See modify image variables
yum_packages	[]	Provide a list of packages to install via yum
yum_repos_dir_path	None	Optional path of directory to be used as /etc/yum.repos.d during the update

Variables used for dev install

Name	Default Value	Description
source_image	[undefined]	See modify image variables
modified_append_tag	date +-modified-%Y%m%d%H%M%S	See modify image variables
target_image	''	See modify image variables
refspecs	[]	An array of project/refspec pairs that will be installed into the generated container. Currently only supports python source projects.
python_dir	[]	Directory which contains a Python project ready to be installed with pip.

Requirements

• ansible >= 2.4
• python >= 2.6

Dependencies

None

Warnings

On-disk repositories

Please ensure the SELinux label for the on-disk repositories are correct. Depending on your container-selinux (and podman) version, you may face issues.

Some examples of a correct type:

• `system_u:object_r:rpm_var_cache_t`
• `system_u:object_r:container_file_t`

First one matches the one of /var/cache/dnf, and is accessible from within a container, while the second one may allow a container to actually write in there.

Directories located in the user's home

You may want to avoid pointing to directories in your $HOME when running this role, especially when it's running from within TripleO client (for instance with the `openstack tripleo container image prepare` command). Doing so may break due to the SELinux labels and permissions associated to your home directory.

Please use another location, such as /opt, or even /tmp - and double-check the SELinux labels therein.

Example Playbooks

Modify Image

The following playbook will produce a modified image with the tag :latest-modified-<timestamp> based on the Dockerfile in the custom directory /path/to/example_modify_dir.

- hosts: localhost
  tasks:
  - name: include ansible-role-tripleo-modify-image
    import_role:
      name: ansible-role-tripleo-modify-image
      tasks_from: modify_image.yml
    vars:
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      modify_dir_path: /path/to/example_modify_dir

The directory example_modify_dir contains the Dockerfile which will perform the modification, for example:

# This will be replaced in the file Dockerfile.modified
FROM centos-binary-nova-api

# switch to root to install packages
USER root

# install packages
RUN curl "https://bootstrap.pypa.io/get-pip.py" -o "/tmp/get-pip.py"
RUN python /tmp/get-pip.py

# switch the container back to the default user
USER nova

Yum update

The following playbook will produce a modified image with the tag :latest-updated which will do a yum update using the host's /etc/yum.repos.d. Only file repositories will be used (with baseurl=file://...). In this playbook the tasks_from is set as a variable instead of an import_role parameter.

- hosts: localhost
  tasks:
  - name: include ansible-role-tripleo-modify-image
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: yum_update.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      yum_repos_dir_path: /etc/yum.repos.d
      modified_append_tag: updated
      yum_cache: /tmp/containers-updater/yum_cache
      rpms_path: /opt/rpms

- hosts: localhost
  tasks:
  - name: include ansible-role-tripleo-modify-image
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: yum_update.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      modified_append_tag: updated
      rpms_path: /opt/rpms/

Note, if you have a locally installed gating repo, you can add update_repo: gating-repo. This may be the case for the consequent in-place deployments, like those performed with the CI reproducer script.

Yum install

The following playbook will produce a modified image with the tag :latest-updated which will do a yum install of the requested packages using the host's /etc/yum.repos.d. In this playbook the tasks_from is set as a variable instead of an import_role parameter.

- hosts: localhost
  tasks:
  - name: include ansible-role-tripleo-modify-image
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: yum_install.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      yum_repos_dir_path: /etc/yum.repos.d
      yum_packages: ['foobar-nova-plugin', 'fizzbuzz-nova-plugin']

RPM install

The following playbook will produce a modified image with RPMs from the specified rpms_path on the local filesystem installed as a new layer for the container. The new container tag is appened with the '-hotfix' suffix. Useful for creating adhoc hotfix containers with local RPMs with no network connectivity.

- hosts: localhost
  tasks:
  - name: include ansible-role-tripleo-modify-image
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: rpm_install.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      rpms_path: /opt/rpms
      modified_append_tag: -hotfix

Dev install

The following playbook will produce a modified image with Python source code installed via pip. To minimize dependencies within the container we generate the sdist locally and then copy it into the resulting container image as an sdist tarball to run pip install locally.

It can be used to pull a review from OpenDev Gerrit:

- hosts: localhost
  connection: local
  tasks:
  - name: dev install heat-api
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: dev_install.yml
      source_image: docker.io/tripleomaster/centos-binary-heat-api:current-tripleo
      refspecs:
        -
          project: heat
          refspec: refs/changes/12/1234/3
      modified_append_tag: -devel

or it can be used to build an image from a local Python directory:

- hosts: localhost
  connection: local
  tasks:
  - name: dev install heat-api
    import_role:
      name: ansible-role-tripleo-modify-image
    vars:
      tasks_from: dev_install.yml
      source_image: docker.io/tripleomaster/centos-binary-heat-api:current-tripleo
      modified_append_tag: -devel
      python_dir:
        - /home/joe/git/openstack/heat

Note: here, we can use a directory located in the user's home because it's probably launched by the user.

License

Apache 2.0