Helm

You must have Helm 3.0 installed for this functionality to work.

Helm is an automation tool for creating all the Kubernetes resources needed to deploy a single application. This is done by creating a “Chart” that describes the components of your installation. When a chart is instantiated, a “Release” is created.

The helm_install() function makes some assumptions about the environment. Values for charts are placed in a subdirectory name charts/. If you don’t provide a release_name, it is derived from the last word in the chart_name. For example, if the chart_name is “stable/tomcat”, “tomcat” is the release name.

Finally, the YAML file with modified values are stored using the following naming pattern: charts/{{release_name}}-values.yaml

A directory structure would look like this:

my-project/
    charts/
        tomcat-values.yaml

    deploy.py

Let’s say the only thing we want to modify on the Tomcat chart was ingress information. The contents of tomcat-values.yaml would look like this:

ingress:
  enabled: true
  hosts:
    - tomcat.{{domain}}
  tls:
    - hosts:
        - tomcat.{{domain}}

Note that we are using Jinja2 templating syntax. When we call helm_install, we can provide the value of all template variables in the param parameters.

You can see this in the following example of deploy.py:

from k9.helm import *
form k9.core import set_default_namespace()

// Set the namespace to install into
set_default_namespace('tomcat')
helm_install('stable/tomcat', {'domain': 'sandbox.simoncomputing.com'})

In the above example, what will happen is the charts/tomcat-values.yaml file will be translated using Jinja to another file .output/tomcat-values.yaml. That file will look like this:

ingress:
  enabled: true
  hosts:
    - tomcat.sandbox.simoncomputing.com
  tls:
    - hosts:
        - tomcat.sandbox.simoncomputing.com

From that point the helm command is called like this:

helm install -f .output/tomcat-values.yaml tomcat stable/tomcat

Note that all Helm functions will throw an exception if an error occurs.

k9.helm.helm_repo_add(repo_name: str, repo_url: str)

Adds the repository to the current kubernetes environment.

Parameters

• repo_name – Local name of repository

• repo_url – URL of repository

Returns

output string on success, exception if failure.

k9.helm.helm_repo_update()

Update the local copy of the repository with the current repository.

Returns

output string on success, exception if failure.

k9.helm.helm_repo_ls()

Lists available repositories.

Returns

Object derived from JSON output, exception on failure.

k9.helm.helm_repo_remove(repo_name: str)

Removes a repository.

Parameters

repo_name –

Returns

output string on success, exception if failure.

k9.helm.helm_install(chart_name: str, params, release_name: Optional[str] = None, values_path: Optional[str] = None, debug=False, namespace: Optional[str] = None)

Runs the Helm installation for the specified chart. Before the chart is installed, the values file which should have the same name as the release_name will be evaluated with Jinja, using the parameters to build the new values file.

The values file is written to the .output/{{release-name}}-values.yaml.

Helm installation is run with this ‘values.yaml’ file and on the default namespace set using set_default_namespace()

Parameters

• chart_name – Name of Chart.

• params – Parameter values in a Dictionary used when pre-processing values. If it is not a dictionary, the vars() function is run on the object to create a dictionary.

• release_name – If None - release_name is defaulted to the last word in chart_name. For example if chart_name is “stable/tomcat”, the release_name is “tomcat”. Release name is also used to construct the charts values file in the following format: ./charts/{{release_name}}-values.yaml

• values_path – Override values file location

• debug – If True, runs Helm with –debug and –dry-run, which will not actually run and displays the chart values. Default is False.

• namespace – Namespace to install the chart on. If None, we use the default namespace.

Returns

output string on success, exception if failure.

k9.helm.helm_uninstall(release_name: str, namespace: Optional[str] = None)

Uninstalls the specified release.

Parameters

• release_name – Name of the release you want to uninstall.

• namespace – Namespace to uninstall the chart from. If None, we use the default namespace.

Returns

Returns output value from uninstall process. Otherwise, throws exception.

k9.helm.helm_ls(namespace: Optional[str] = None)

Lists all current helm installations.

Parameters

namespace – Namespace to list charts from. If None, we use the default namespace.

Returns

List of all helm installations. Throws exception on error.

Sample Output:

[
    {"name":"tomcat",
    "namespace":"default",
    "revision":"1",
    "updated":"2019-12-10 18:28:43.753814 -0500 EST",
    "status":"deployed",
    "chart":"tomcat-0.4.0",
    "app_version":"7.0"}
]

k9.helm.helm_exists(release_name: str, namespace: Optional[str] = None)

Returns true if the specified release_name exist.

Parameters

• release_name – Name of release.

• namespace – Namespace to check for the chart in. If None, we use the default namespace.

Returns

True if found.