An Operator Bundle
is a container image that stores Kubernetes manifests and metadata associated with an operator. A bundle is meant to present a specific version of an operator.
The operator manifests refers to a set of Kubernetes manifest(s) the defines the deployment and RBAC model of the operator. The operator metadata on the other hand are, but not limited to:
- Information that identifies the operator, its name, version etc.
- Additional information that drives the UI:
- Icon
- Example CR(s)
- Channel(s)
- API(s) provided and required.
- Related images.
An Operator Bundle
is built as a scratch (non-runnable) container image that contains operator manifests and specific metadata in designated directories inside the image. Then, it can be pushed and pulled from an OCI-compliant container registry. Ultimately, an operator bundle will be used by Operator Registry and Operator-Lifecycle-Manager (OLM) to install an operator in OLM-enabled clusters.
We use the following labels to annotate the operator bundle image.
- The label
operators.operatorframework.io.bundle.mediatype.v1
reflects the media type or format of the operator bundle. It could be helm charts, plain Kubernetes manifests etc. - The label
operators.operatorframework.io.bundle.manifests.v1
reflects the path in the image to the directory that contains the operator manifests. - The label
operators.operatorframework.io.bundle.metadata.v1
reflects the path in the image to the directory that contains metadata files about the bundle. - The
manifests.v1
andmetadata.v1
labels imply the bundle type:- The value
manifests.v1
implies that this bundle contains operator manifests. - The value
metadata.v1
implies that this bundle has operator metadata.
- The value
- The label
operators.operatorframework.io.bundle.package.v1
reflects the package name of the bundle. - The label
operators.operatorframework.io.bundle.channels.v1
reflects the list of channels the bundle is subscribing to when added into an operator registry - The label
operators.operatorframework.io.bundle.channel.default.v1
reflects the default channel an operator should be subscribed to when installed from a registry
The labels will also be put inside a YAML file, as shown below.
annotations.yaml
annotations:
operators.operatorframework.io.bundle.mediatype.v1: "registry+v1"
operators.operatorframework.io.bundle.manifests.v1: "manifests/"
operators.operatorframework.io.bundle.metadata.v1: "metadata/"
operators.operatorframework.io.bundle.package.v1: "test-operator"
operators.operatorframework.io.bundle.channels.v1: "beta,stable"
operators.operatorframework.io.bundle.channel.default.v1: "stable"
Notes:
- In case of a mismatch, the
annotations.yaml
file is authoritative because the on-cluster operator-registry that relies on these annotations has access to the yaml file only. - The potential use case for the
LABELS
is - an external off-cluster tool can inspect the image to check the type of a given bundle image without downloading the content.
This example uses Operator Registry Manifests format to build an operator bundle image. The source directory of an operator registry bundle has the following layout.
$ tree test
test
├── testbackup.crd.yaml
├── testcluster.crd.yaml
├── testoperator.v0.1.0.clusterserviceversion.yaml
├── testrestore.crd.yaml
└── metadata
└── annotations.yaml
This is an example of a Dockerfile
for operator bundle:
FROM scratch
# We are pushing an operator-registry bundle
# that has both metadata and manifests.
LABEL operators.operatorframework.io.bundle.mediatype.v1=registry+v1
LABEL operators.operatorframework.io.bundle.manifests.v1=manifests/
LABEL operators.operatorframework.io.bundle.metadata.v1=metadata/
LABEL operators.operatorframework.io.bundle.package.v1=test-operator
LABEL operators.operatorframework.io.bundle.channels.v1=beta,stable
LABEL operators.operatorframework.io.bundle.channel.default.v1=stable
ADD test/*.yaml /manifests
ADD test/metadata/annotations.yaml /metadata/annotations.yaml
Below is the directory layout of the operator bundle inside the image:
$ tree
/
├── manifests
│ ├── testbackup.crd.yaml
│ ├── testcluster.crd.yaml
│ ├── testoperator.v0.1.0.clusterserviceversion.yaml
│ └── testrestore.crd.yaml
└── metadata
└── annotations.yaml
Operator SDK CLI is available to generate Bundle annotations and Dockerfile based on provided operator manifests.
In order to use Operator SDK CLI, follow the operator-SDK installation instruction:
- Install the Operator SDK CLI
Now, a binary named operator-sdk
is available in OLM's directory to use.
$ ./operator-sdk
An SDK for building operators with ease
Usage:
operator-sdk [command]
Available Commands:
bundle Operator bundle commands
Flags:
-h, --help help for operator-sdk
--verbose Enable verbose logging
Use "operator-sdk [command] --help" for more information about a command.
Notes:
- If there are
annotations.yaml
andDockerfile
existing in the directory, they will be overwritten.
Using operator-sdk
CLI, bundle annotations can be generated from provided operator manifests. The overall bundle generate
command usage is:
Usage:
operator-sdk bundle generate [flags]
Flags:
-c, --channels string The list of channels that bundle image belongs to
-e, --default string The default channel for the bundle image
-d, --directory string The directory where bundle manifests for a specific version are located.
-h, --help help for generate
-p, --package string The name of the package that bundle image belongs to
Note:
* All manifests yaml must be in the same directory.
The --directory/-d
, --channels/-c
, --package/-p
are required flags while --default/-e
is optional.
The command for generate
task is:
$ ./operator-sdk bundle generate --directory /test --package test-operator \
--channels stable,beta --default stable
The --directory
or -d
specifies the directory where the operator manifests are located. The Dockerfile
is generated in the same directory where the YAML manifests are located while the annotations.yaml
file is located in a folder named metadata
. For example:
$ tree test
test
├── testbackup.crd.yaml
├── testcluster.crd.yaml
├── testoperator.v0.1.0.clusterserviceversion.yaml
├── testrestore.crd.yaml
├── metadata
│ └── annotations.yaml
└── Dockerfile
The --package
or -p
is the name of package fo the operator such as etcd
which which map channels
to a particular application definition. channels
allow package authors to write different upgrade paths for different users (e.g. beta
vs. stable
). The channels
list is provided via --channels
or -c
flag. Multiple channels
are separated by a comma (,
). The default channel is provided optionally via --default
or -e
flag. If the default channel is not provided, the first channel in channel list is selected as default.
All information in annotations.yaml
is also existed in LABEL
section of Dockerfile
.
The Dockerfile
can be used manually to build the bundle image using container image tools such as Docker, Podman or Buildah. For example, the Docker build command would be:
$ docker build -f /path/to/Dockerfile -t quay.io/test/test-operator:latest /path/to/manifests/
Operator bundle image can be built from provided operator manifests using build
command (see Notes below). The overall bundle build
command usage is:
Usage:
operator-SDK bundle build [flags]
Flags:
-c, --channels string The list of channels that bundle image belongs to
-e, --default string The default channel for the bundle image
-d, --directory string The directory where bundle manifests for a specific version are located
-h, --help help for build
-b, --image-builder string Tool to build container images. One of: [docker, podman, buildah] (default "docker")
-0, --overwrite To overwrite annotations.yaml if existing
-p, --package string The name of the package that bundle image belongs to
-t, --tag string The name of the bundle image will be built
Note:
* Bundle image is not runnable.
* All manifests yaml must be in the same directory.
The command for build
task is:
$ ./operator-sdk bundle build --directory /test --tag quay.io/coreos/test-operator.v0.1.0:latest \
--package test-operator --channels stable,beta --default stable
The --directory
or -d
specifies the directory where the operator manifests for a specific version are located. The --tag
or -t
specifies the image tag that you want the operator bundle image to have. By using build
command, the annotations.yaml
and Dockerfile
are automatically generated in the background.
The default image builder is Docker
. However, Buildah
and Podman
are also supported. An image builder can specified via --image-builder
or -b
optional tag in build
command. For example:
$ ./operator-sdk bundle build --directory /test/0.1.0/ --tag quay.io/coreos/test-operator.v0.1.0:latest \
--image-builder podman --package test-operator --channels stable,beta --default stable
The --package
or -p
is the name of package fo the operator such as etcd
which which map channels
to a particular application definition. channels
allow package authors to write different upgrade paths for different users (e.g. beta
vs. stable
). The channels
list is provided via --channels
or -c
flag. Multiple channels
are separated by a comma (,
). The default channel is provided optionally via --default
or -e
flag. If the default channel is not provided, the first channel in channel list is selected as default.
Notes:
- If there is
Dockerfile
existing in the directory, it will be overwritten. - If there is an existing
annotations.yaml
in/metadata
directory, the cli will attempt to validate it and returns any found errors. If theannotations.yaml
is valid, it will be used as a part of build process. The optional boolean--overwrite/-o
flag can be enabled (false by default) to allow cli to overwrite theannotations.yaml
if existed.
Operator bundle image can validate bundle image that is publicly available in an image registry using validate
command (see Notes below). The overall bundle validate
command usage is:
Usage:
operator-SDK bundle validate [flags]
Flags:
-t, --tag string The name of the bundle image will be built
-b, --image-builder string Tool to extract container images. One of: [docker, podman] (default "docker")
-h, --help help for build
The command for validate
task is:
$ ./operator-sdk bundle build --tag quay.io/coreos/test-operator.v0.1.0:latest --image-builder docker
The validate
command will first extract the contents of the bundle image into a temporary directory after it pulls the image from its image registry. Then, it will validate the format of bundle image to ensure manifests and metadata are located in their appropriate directories (/manifests/
for bundle manifests files such as CSV and /metadata/
for metadata files such as annotations.yaml
). Also, it will validate the information in annotations.yaml
to confirm that metadata is matching the provided data. For example, the provided media type in annotations.yaml just matches the actual media type is provided in the bundle image.
After the bundle image format is confirmed, the command will validate the bundle contents such as manifests and metadata files only if the bundle format is RegistryV1
type meaning it contains ClusterResourceVersion
and its associated Kubernetes objects that makes up an Operator. The content validation process will ensure the individual file in the bundle image is valid and can be applied to an OLM-enabled cluster provided all necessary permissions and configurations are met.
Notes:
- The bundle content validation is best effort which means it will not guarantee 100% accuracy due to nature of Kubernetes objects may need certain permissions and configurations, which users may not have, in order to be applied successfully in a cluster.