katenary/doc/docs/labels.md

Labels documentation

Katenary proposes labels to set in compose.yaml files (or override files) to configure the Helm Chart generation. Because it is sometimes needed to have structured values, it is necessary to use the Yaml syntax. While compose labels are string, we can use | to use Yaml multilines as value.

Katenary will try to Unmarshal these labels.

Label list and types

Label name	Description	Type
katenary.v3/configmap-files	Add files to the configmap.	[]string
katenary.v3/cronjob	Create a cronjob from the service.	object
katenary.v3/dependencies	Add Helm dependencies to the service.	[]object
katenary.v3/description	Description of the service	string
katenary.v3/env-from	Add environment variables from antoher service.	[]string
katenary.v3/exchange-volumes	Add exchange volumes (empty directory on the node) to share data	[]object
katenary.v3/health-check	Health check to be added to the deployment.	object
katenary.v3/ignore	Ignore the service	bool
katenary.v3/ingress	Ingress rules to be added to the service.	object
katenary.v3/main-app	Mark the service as the main app.	bool
katenary.v3/map-env	Map env vars from the service to the deployment.	map[string]string
katenary.v3/ports	Ports to be added to the service.	[]uint32
katenary.v3/same-pod	Move the same-pod deployment to the target deployment.	string
katenary.v3/secrets	Env vars to be set as secrets.	[]string
katenary.v3/values	Environment variables to be added to the values.yaml	[]string or map[string]string
katenary.v3/values-from	Add values from another service.	map[string]string

Detailed description

katenary.v3/configmap-files

Add files to the configmap.

Type: []string

It makes a file or directory to be converted to one or more ConfigMaps and mounted in the pod. The file or directory is relative to the service directory.

If it is a directory, all files inside it are added to the ConfigMap.

If the directory as subdirectories, so one configmap per subpath are created.

!!! Warning It is not intended to be used to store an entire project in configmaps. It is intended to be used to store configuration files that are not managed by the application, like nginx configuration files. Keep in mind that your project sources should be stored in an application image or in a storage.

Example:

volumes
  - ./conf.d:/etc/nginx/conf.d
labels:
  katenary.v3/configmap-files: |-
    - ./conf.d

katenary.v3/cronjob

Create a cronjob from the service.

Type: object

This adds a cronjob to the chart.

The label value is a YAML object with the following attributes:

• command: the command to be executed
• schedule: the cron schedule (cron format or @every where "every" is a duration like 1h30m, daily, hourly...)
• rbac: false (optionnal), if true, it will create a role, a rolebinding and a serviceaccount to make your cronjob able to connect the Kubernetes API

Example:

labels:
    katenary.v3/cronjob: |-
        command: echo "hello world"
        schedule: "* */1 * * *" # or @hourly for example

katenary.v3/dependencies

Add Helm dependencies to the service.

Type: []object

Set the service to be, actually, a Helm dependency. This means that the service will not be exported as template. The dependencies are added to the Chart.yaml file and the values are added to the values.yaml file.

It's a list of objects with the following attributes:

• name: the name of the dependency
• repository: the repository of the dependency
• alias: the name of the dependency in values.yaml (optional)
• values: the values to be set in values.yaml (optional)

!!! Info Katenary doesn't update the helm depenedencies by default.

Use `--helm-update` (or `-u`) flag to update the dependencies.

example: <code>katenary convert -u</code>

By setting an alias, it is possible to change the name of the dependency in values.yaml.

Example:

labels:
  katenary.v3/dependencies: |-
    - name: mariadb
      repository: oci://registry-1.docker.io/bitnamicharts

      ## optional, it changes the name of the section in values.yaml
      # alias: mydatabase

      ## optional, it adds the values to values.yaml
      values:
        auth:
          database: mydatabasename
          username: myuser
          password: the secret password

katenary.v3/description

Description of the service

Type: string

This replaces the default comment in values.yaml file to the given description. It is useful to document the service and configuration.

The value can be set with a documentation in multiline format.

Example:

labels:
  katenary.v3/description: |-
    This is a description of the service.
    It can be multiline.

katenary.v3/env-from

Add environment variables from antoher service.

Type: []string

It adds environment variables from another service to the current service.

Example:

service1:
  image: nginx:1.19
  environment:
      FOO: bar

service2:
  image: php:7.4-fpm
  labels:
    # get the congigMap from service1 where FOO is 
    # defined inside this service too
    katenary.v3/env-from: |-
        - myservice1

katenary.v3/exchange-volumes

Add exchange volumes (empty directory on the node) to share data

Type: []object

This label allows sharing data between containres. The volume is created in the node and mounted in the pod. It is useful to share data between containers in a "same pod" logic. For example to let PHP-FPM and Nginx share the same direcotory.

This will create:

• an emptyDir volume in the deployment
• a voumeMount in the pod for each container
• a initContainer for each definition

Fields:

• name: the name of the volume (manadatory)
• mountPath: the path where the volume is mounted in the pod (optional, default is /opt)
• init: a command to run to initialize the volume with data (optional)

!!! Warning This is highly experimental. This is mainly useful when using the "same-pod" label.

Example:

nginx:
  # ...
  labels;
    katenary.v3/exchange-volumes: |-
      - name: php-fpm
        mountPath: /var/www/html
php:
  # ...
  labels:
    katenary.v3/exchange-volumes: |-
      - name: php-fpm
        mountPath: /opt
        init: cp -ra /var/www/html/* /opt

katenary.v3/health-check

Health check to be added to the deployment.

Type: object

Health check to be added to the deployment.

Example:

labels:
  katenary.v3/health-check: |-
    livenessProbe:
      httpGet:
        path: /health
        port: 8080

katenary.v3/ignore

Ignore the service

Type: bool

Ingoring a service to not be exported in helm chart.

Example:

labels:
  katenary.v3/ignore: "true"

katenary.v3/ingress

Ingress rules to be added to the service.

Type: object

Declare an ingress rule for the service. The port should be exposed or declared with katenary.v3/ports.

Example:

labels:
  katenary.v3/ingress: |-
    port: 80
    hostname: mywebsite.com (optional)

katenary.v3/main-app

Mark the service as the main app.

Type: bool

This makes the service to be the main application. Its image tag is considered to be the Chart appVersion and to be the defaultvalue in Pod container image attribute.

!!! Warning This label cannot be repeated in others services. If this label is set in more than one service as true, Katenary will return an error.

Example:

ghost:
  image: ghost:1.25.5
  labels:
    # The chart is now named ghost, and the appVersion is 1.25.5.
    # In Deployment, the image attribute is set to ghost:1.25.5 if 
    # you don't change the "tag" attribute in values.yaml
    katenary.v3/main-app: true

katenary.v3/map-env

Map env vars from the service to the deployment.

Type: map[string]string

Because you may need to change the variable for Kubernetes, this label forces the value to another. It is also particullary helpful to use a template value instead. For example, you could bind the value to a service name with Helm attributes: {{ tpl .Release.Name . }}.

If you use __APP__ in the value, it will be replaced by the Chart name.

Example:

env:
  DB_HOST: database
  RUNNING: docker
  OTHER: value
labels:
  katenary.v3/map-env: |-
    RUNNING: kubernetes
    DB_HOST: '{{ include "__APP__.fullname" . }}-database'

katenary.v3/ports

Ports to be added to the service.

Type: []uint32

Only useful for services without exposed port. It is mandatory if the service is a dependency of another service.

Example:

labels:
  katenary.v3/ports: |-
    - 8080
    - 8081

katenary.v3/same-pod

Move the same-pod deployment to the target deployment.

Type: string

This will make the service to be included in another service pod. Some services must work together in the same pod, like a sidecar or a proxy or nginx + php-fpm.

Note that volume and VolumeMount are copied from the source to the target deployment.

Example:

web:
  image: nginx:1.19

php:
  image: php:7.4-fpm
  labels:
    katenary.v3/same-pod: web

katenary.v3/secrets

Env vars to be set as secrets.

Type: []string

This label allows setting the environment variables as secrets. The variable is removed from the environment and added to a secret object.

The variable can be set to the katenary.v3/values too, so the secret value can be configured in values.yaml

Example:

env:
  PASSWORD: a very secret password
  NOT_A_SECRET: a public value
labels:
  katenary.v3/secrets: |-
    - PASSWORD

katenary.v3/values

Environment variables to be added to the values.yaml

Type: []string or map[string]string

By default, all environment variables in the "env" and environment files are added to configmaps with the static values set. This label allows adding environment variables to the values.yaml file.

Note that the value inside the configmap is {{ tpl vaname . }}, so you can set the value to a template that will be rendered with the values.yaml file.

The value can be set with a documentation. This may help to understand the purpose of the variable.

Example:

env:
  FOO: bar
  DB_NAME: mydb
  TO_CONFIGURE: something that can be changed in values.yaml
  A_COMPLEX_VALUE: example
labels:
  katenary.v3/values: |-
    # simple values, set as is in values.yaml
    - TO_CONFIGURE
    # complex values, set as a template in values.yaml with a documentation
    - A_COMPLEX_VALUE: |-
        This is the documentation for the variable to 
        configure in values.yaml.
        It can be, of course,  a multiline text.

katenary.v3/values-from

Add values from another service.

Type: map[string]string

This label allows adding values from another service to the current service. It avoid duplicating values, environment or secrets that should be the same.

The key is the value to be added, and the value is the "key" to fetch in the form service_name.environment_name.

Example:

database:
  image: mariadb:10.5
  environment:
    MARIADB_USER: myuser
    MARIADB_PASSWORD: mypassword
  labels:
    # it can be a secret
    katenary.v3/secrets: |-
      - DB_PASSWORD
php:
  image: php:7.4-fpm
  environment:
    # it's duplicated in docker / podman
    DB_USER: myuser
    DB_PASSWORD: mypassword
  labels:
    # removes the duplicated, use the configMap and secrets from "database"
    katenary.v3/values-from: |-
      DB_USER: database.MARIADB_USER
      DB_PASSWORD: database.MARIADB_PASSWORD