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
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
compare_host_packages	False	If True, skip yum update when package versions match host package versions

Requirements

• ansible >= 2.4
• python >= 2.6
• docker-py >= 1.7.0
• Docker API >= 1.20

Dependencies

None

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 tripleo-modify-image
    import_role:
      name: 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. The yum update will only occur if there are differences between host and image package versions. In this playbook the tasks_from is set as a variable instead of an import_role parameter.

- hosts: localhost
  tasks:
  - name: include tripleo-modify-image
    import_role:
      name: tripleo-modify-image
    vars:
      tasks_from: yum_update.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      compare_host_packages: true
      yum_repos_dir_path: /etc/yum.repos.d
      modified_append_tag: updated

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 tripleo-modify-image
    import_role:
      name: tripleo-modify-image
    vars:
      tasks_from: rpm_install.yml
      source_image: docker.io/tripleomaster/centos-binary-nova-api:latest
      rpms_path: /foo/bar
      modified_append_tag: -hotfix

License

Apache 2.0