Helm install
External
Internal
Overview
helm install installs a chart, that may come from different sources, and creates a release:
helm install <release-name> <chart> [options]
The release name must be specified explicitly, and it must be the first argument. If it should be generated, --generate-name must be used instead of the release name.
Chart Sources
There are five types of chart sources:
- Unpacked charts on the local filesystem
- tgz packaged chart on the local filesystem
- Absolute URL of a chart archive in a remote repository
- Chart reference in a remote repository
- Chart is present in a locally cached repository, and specified by its chart name and repository prefix
Path to an Unpacked Chart
The chart argument of the install command can be an unpacked local chart directory. The directory name must be identical with the chart name specified in Chart.yaml).
helm install simplest ./playground/helm/simplest
Path to a Packaged Chart
helm install simplest ./simplest-1.0.0.tgz
Charts can be packaged with helm package command.
Where is the chart expanded locally?
Absolute URL
The absolute URL of a chart can be used as such:
helm install something https://example.com/charts/something-1.0.0.tgz
The version is built into the name of the chart, this is the default Helm versioning convention. The chart does not need to be cached in the local repository and the repository does not need to be cached locally with repo add.
If the remote repository is password-protected, the username and the password can be specified on the command line with:
helm install something https://example.com/charts/something-1.0.0.tgz --username <username> --password <password>
Where is the chart expanded locally?
Chart Reference
A chart available in a chart repository can be specified by a chart reference (which is the same thing as the chart name) when installed. There are two ways to specify a chart reference:
Using an Explicit Repository URL with --repo
A repository URL can be specified in-line in the install command line with --repo, without being previously added with helm repo add:
helm install --repo https://example.com/charts/ mynginx [--version 1.2.3] nginx
If --version is not specified, the latest present version is installed.
Where is the chart expanded locally?
Using a Repository Prefix
If the repository was added locally under a specific name ("myRepository" in the example below), then the chart can be referred by <repository-name>/<chart-name>. If no version specification is provided, the latest stable version of the chart will be installed:
helm install postgresql myRepository/postgresql
A specific version can be requested with --version.
helm install postgresql --version 1.2.3 myRepository/postgresql
The charts available in the repository can be listed with:
helm search repo myRepository
helm install and Dependencies
If the chart has dependencies, they must be present in the charts/ subdirectory at the time of the installation. helm install does not manage dependencies, helm dependency does. helm install performs some sanity checks, such as comparing the content of requirements.yaml with the content of the charts/ subdirectory and failing if requirements.yaml contains dependencies that are not in charts/. However, if a dependency is present in charts/ but not in requirements.yaml, it will be installed. For more details on dependencies and how they work, see:
TODO: --dependency-update.
Overriding Default Configuration or Providing New Cofiguration
-f|--values
Default configuration can be overridden or new configuration can be specified with:
helm install -f|--values <configuration-overrides-file.yaml> <chart name>
The -f|--values flag can be specified multiple times on the command line, and the rightmost value will take precedence. The effective configuration actually applied to the chart is computed by using the chart's values.yaml as base and then logically overlaying the configuration files from left to right. An overlay step leaves configuration paths that exist in the base but are not present in the overlay unchanged, overwrites configuration paths that are present both in the base and the overlay with the value present in the overlay, and adds new configuration paths that do not exist in the base but exist in the overlay. The process is repeated from left to right for all files present on command line.
For more details on Helm configuration see:
--set-file
--set-file stringArray
"names" the content of a file, and makes it available from templates using the name. Set values from respective files specified via the command line. Multiple or separate values can be specified as key1=path1,key2=path2)
TODO:
--set-file certificate=/path/to/the/file
then call .Values.certificate in the template to access the file's data.
For more details on Helm configuration see:
--set, --set--string
Individual configuration options can be specified with --set or --set-string.
helm install --set size=10 <chart name>
For more details on overriding or specifying configuration see:
Overriding Tags and Conditions
Use --set to override default tag and condition values at installation time.
Options
Generic Options
--generate-name
Generate a release name:
helm install --generate-name <chart>
If used, the user-supplied name must be omitted from the command line, and a name based on the chart name will be generated. If the chart is named "simplest", the generated name is similar to "simplest-1-1575057340".
--dry-run
In this mode, the installation is simulated, without actually modifying anything on the Kubernetes cluster. Instead of installing the chart, the rendered template are sent to stdout so they can be inspected. Note that in this mode, it is not guaranteed that Kubernetes cluster will accept the generated manifest.
helm install --dry-run ...
--dry-run can be combined with --debug for more information:
helm install --dry-run --debug ...
--debug
helm install --debug ...
The --debug flag displays:
--verify
If --verify is used, the chart must have a provenance file, and the provenance file must pass all verification steps.
--atomic
Installation process purges chart on fail. The --wait flag will be set automatically if --atomic is used.
--version
Specify the exact chart version to install. If this is not specified, the latest version is installed.
--dependency-update
Run helm dependency update before installing the chart. TODO: more research here.
--name-template
Specify template used to name the release.
--output
Prints the output in the specified format. Allowed values: table, json, yaml (default table).
--wait
If set, Helm will wait until all Pods, PVCs, Services, and minimum number of Pods of a Deployment, StatefulSet, or ReplicaSet are in a ready state before marking the release as successful. It will wait for as long as --timeout:
helm instal ... --wait --timeout 60s
If timeout occurs, the helm command will exit with a non-zero exit code, but the installation will continue and it may eventually succeed.
--timeout
The time to wait for any individual Kubernetes operation. The default value is 5 minutes.
helm install --timeout 5m0s
Also see --wait above.
--replace
Also see helm uninstall - Keep a Resource from being Uninstalled to understand implication on orphaned resources.
--username, --password
See Absolute URL of a chart in a remote repository above.
-n,--namespace
Specifies the namespace scope for this installation.
helm install -n test blue ./src/mian/helm/blue
Note that the namespace must exist, otherwise Helm installation will fail:
Error: create: failed to create: namespaces "test" not found
The namespace specified with -n can be retrieved in templates with the .Release.Namespace built-in object.
--create-namespace
Create the release namespace if not present.
Scenarios
Using External Files during Installation
TODO: