README.md

Helmfile

Deploy Kubernetes Helm Charts

Status

Even though Helmfile is used in production environments across multiple organizations, it is still in its early stage of development, hence versioned 0.x.

Helmfile complies to Semantic Versioning 2.0.0 in which v0.x means that there could be backward-incompatible changes for every release.

Note that we will try our best to document any backward incompatibility. And in reality, helmfile had no breaking change for a year or so.

About

Helmfile is a declarative spec for deploying helm charts. It lets you...

• Keep a directory of chart value files and maintain changes in version control.
• Apply CI/CD to configuration changes.
• Periodically sync to avoid skew in environments.

To avoid upgrades for each iteration of helm, the helmfile executable delegates to helm - as a result, helm must be installed.

Highlights

Declarative: Write, version-control, apply the desired state file for visibility and reproducibility.

Modules: Modularize common patterns of your infrastructure, distribute it via Git, S3, etc. to be reused across the entire company (See #648)

Versatility: Manage your cluster consisting of charts, kustomizations, and directories of Kubernetes resources, turning everything to Helm releases (See #673)

Patch: JSON/Strategic-Merge Patch Kubernetes resources before helm-installing, without forking upstream charts (See #673)

Configuration

CAUTION: This documentation is for the development version of Helmfile. If you are looking for the documentation for any of releases, please switch to the corresponding release tag like v0.79.1.

The default helmfile is helmfile.yaml:

# Chart repositories used from within this state file
#
# Use `helm-s3` and `helm-git` and whatever Helm Downloader plugins
# to use repositories other than the official repository or one backend by chartmuseum.
repositories:
# To use official "stable" charts a.k.a https://github.com/helm/charts/tree/master/stable
- name: stable
  url: https://kubernetes-charts.storage.googleapis.com
# To use official "incubator" charts a.k.a https://github.com/helm/charts/tree/master/incubator
- name: incubator
  url: https://kubernetes-charts-incubator.storage.googleapis.com
# helm-git powered repository: You can treat any Git repository as a charts repository
- name: polaris
  url: git+https://github.com/reactiveops/polaris@deploy/helm?ref=master
# Advanced configuration: You can setup basic or tls auth
- name: roboll
  url: http://roboll.io/charts
  certFile: optional_client_cert
  keyFile: optional_client_key
  username: optional_username
  password: optional_password

# context: kube-context # this directive is deprecated, please consider using helmDefaults.kubeContext

#default values to set for args along with dedicated keys that can be set by contributers, cli args take precedence over these
helmDefaults:
  tillerNamespace: tiller-namespace  #dedicated default key for tiller-namespace
  tillerless: false                  #dedicated default key for tillerless
  kubeContext: kube-context          #dedicated default key for kube-context (--kube-context)
  # additional and global args passed to helm
  args:
    - "--set k=v"
  # defaults for verify, wait, force, timeout and recreatePods under releases[]
  verify: true
  wait: true
  timeout: 600
  recreatePods: true
  force: true
  # enable TLS for request to Tiller
  tls: true
  # path to TLS CA certificate file (default "$HELM_HOME/ca.pem")
  tlsCACert: "path/to/ca.pem"
  # path to TLS certificate file (default "$HELM_HOME/cert.pem")
  tlsCert: "path/to/cert.pem"
  # path to TLS key file (default "$HELM_HOME/key.pem")
  tlsKey: "path/to/key.pem"

# The desired states of Helm releases.
#
# Helmfile runs various helm commands to converge the current state in the live cluster to the desired state defined here.
releases:
  # Published chart example
  - name: vault                            # name of this release
    namespace: vault                       # target namespace
    labels:                                  # Arbitrary key value pairs for filtering releases
      foo: bar
    chart: roboll/vault-secret-manager     # the chart being installed to create this release, referenced by `repository/chart` syntax
    version: ~1.24.1                       # the semver of the chart. range constraint is supported
    missingFileHandler: Warn # set to either "Error" or "Warn". "Error" instructs helmfile to fail when unable to find a values or secrets file. When "Warn", it prints the file and continues.
    # Values files used for rendering the chart
    values:
      # Value files passed via --values
      - vault.yaml
      # Inline values, passed via a temporary values file and --values, so that it doesn't suffer from type issues like --set
      - address: https://vault.example.com
      # Go template available in inline values and values files.
      - image:
          # The end result is more or less YAML. So do `quote` to prevent number-like strings from accidentally parsed into numbers!
          # See https://github.com/roboll/helmfile/issues/608
          tag: {{ requiredEnv "IMAGE_TAG" | quote }}
          # Otherwise:
          #   tag: "{{ requiredEnv "IMAGE_TAG" }}"
          #   tag: !!string {{ requiredEnv "IMAGE_TAG" }}
        db:
          username: {{ requiredEnv "DB_USERNAME" }}
          # value taken from environment variable. Quotes are necessary. Will throw an error if the environment variable is not set. $DB_PASSWORD needs to be set in the calling environment ex: export DB_PASSWORD='password1'
          password: {{ requiredEnv "DB_PASSWORD" }}
        proxy:
          # Interpolate environment variable with a fixed string
          domain: {{ requiredEnv "PLATFORM_ID" }}.my-domain.com
          scheme: {{ env "SCHEME" | default "https" }}
    # Use `values` whenever possible!
    # `set` translates to helm's `--set key=val`, that is known to suffer from type issues like https://github.com/roboll/helmfile/issues/608
    set:
    # single value loaded from a local file, translates to --set-file foo.config=path/to/file
    - name: foo.config
      file: path/to/file
    # set a single array value in an array, translates to --set bar[0]={1,2}
    - name: bar[0]
      values:
      - 1
      - 2
    # set a templated value
    - name: namespace
      value: {{ .Namespace }}
    # will attempt to decrypt it using helm-secrets plugin
    secrets:
      - vault_secret.yaml
    # verify the chart before upgrading (only works with packaged charts not directories)
    verify: true
    # wait for k8s resources via --wait. Defaults to `false`
    wait: true
    # time in seconds to wait for any individual Kubernetes operation (like Jobs for hooks, and waits on pod/pvc/svc/deployment readiness) (default 300)
    timeout: 60
    # performs pods restart for the resource if applicable
    recreatePods: true
    # forces resource update through delete/recreate if needed
    force: true
    # set `false` to uninstall on sync
    installed: true
    # restores previous state in case of failed release
    atomic: true
    # name of the tiller namespace
    tillerNamespace: vault
    # if true, will use the helm-tiller plugin
    tillerless: false
    # enable TLS for request to Tiller
    tls: true
    # path to TLS CA certificate file (default "$HELM_HOME/ca.pem")
    tlsCACert: "path/to/ca.pem"
    # path to TLS certificate file (default "$HELM_HOME/cert.pem")
    tlsCert: "path/to/cert.pem"
    # path to TLS key file (default "$HELM_HOME/key.pem")
    tlsKey: "path/to/key.pem"
    # --kube-context to be passed to helm commands
    # CAUTION: this doesn't work as expected for `tilerless: true`.
    # See https://github.com/roboll/helmfile/issues/642
    kubeContext: kube-context

  # Local chart example
  - name: grafana                            # name of this release
    namespace: another                       # target namespace
    chart: ../my-charts/grafana              # the chart being installed to create this release, referenced by relative path to local helmfile
    values:
    - "../../my-values/grafana/values.yaml"             # Values file (relative path to manifest)
    - ./values/{{ requiredEnv "PLATFORM_ENV" }}/config.yaml # Values file taken from path with environment variable. $PLATFORM_ENV must be set in the calling environment.
    wait: true

#
# Advanced Configuration: Nested States
#
helmfiles:
- # Path to the helmfile state file being processed BEFORE releases in this state file
  path: path/to/subhelmfile.yaml
  # Label selector used for filtering releases in the nested state.
  # For example, `name=prometheus` in this context is equivalent to processing the nested state like
  #   helmfile -f path/to/subhelmfile.yaml -l name=prometheus sync
  selectors:
  - name=prometheus
  # Override state values
  values:
  # Values files merged into the nested state's values
  - additiona.values.yaml
  # Inline state values merged into the nested state's values
  - key1: val1
- # All the nested state files under `helmfiles:` is processed in the order of definition.
  # So it can be used for preparation for your main `releases`. An example would be creating CRDs required by `releases` in the parent state file.
  path: path/to/mycrd.helmfile.yaml
- # Terraform-module-like URL for importing a remote directory and use a file in it as a nested-state file
  # The nested-state file is locally checked-out along with the remote directory containing it.
  # Therefore all the local paths in the file are resolved relative to the file
  path: git::https://github.com/cloudposse/helmfiles.git@releases/kiam.yaml?ref=0.40.0

#
# Advanced Configuration: Environments
#

# The list of environments managed by helmfile.
#
# The default is `environments: {"default": {}}` which implies:
#
# - `{{ .Environment.Name }}` evaluates to "default"
# - `{{ .Environment.Values }}` being empty
environments:
  # The "default" environment is available and used when `helmfile` is run without `--environment NAME`.
  default:
    # Everything from the values.yaml is available via `{{ .Environment.Values.KEY }}`.
    # Suppose `{"foo": {"bar": 1}}` contained in the values.yaml below,
    # `{{ .Environment.Values.foo.bar }}` is evaluated to `1`.
    values:
    - environments/default/values.yaml
    # Each entry in values can be either a file path or inline values.
    # The below is an example of inline values, which is merged to the `.Environment.Values`
    - myChartVer: 1.0.0-dev
  # Any environment other than `default` is used only when `helmfile` is run with `--environment NAME`.
  # That is, the "production" env below is used when and only when it is run like `helmfile --environment production sync`.
  production:
    values:
    - environment/production/values.yaml
    - myChartVer: 1.0.0
    ## `secrets.yaml` is decrypted by `helm-secrets` and available via `{{ .Environment.Secrets.KEY }}`
    secrets:
    - environment/production/secrets.yaml
    # Instructs helmfile to fail when unable to find a environment values file listed under `environments.NAME.values`.
    #
    # Possible values are  "Error", "Warn", "Info", "Debug". The default is "Error".
    #
    # Use "Warn", "Info", or "Debug" if you want helmfile to not fail when a values file is missing, while just leaving
    # a message about the missing file at the log-level.
    missingFileHandler: Error

#
# Advanced Configuration: Layering
#
# Helmfile merges all the "base" state files and this state file before processing.
#
# Assuming this state file is named `helmfile.yaml`, all the files are merged in the order of:
#   environments.yaml <- defaults.yaml <- templates.yaml <- helmfile.yaml
bases:
- environments.yaml
- defaults.yaml
- templates.yaml

Templating

Helmfile uses Go templates for templating your helmfile.yaml. While go ships several built-in functions, we have added all of the functions in the Sprig library.

We also added one special template function: requiredEnv. The requiredEnv function allows you to declare a particular environment variable as required for template rendering. If the environment variable is unset or empty, the template rendering will fail with an error message.

Using environment variables

Environment variables can be used in most places for templating the helmfile. Currently this is supported for name, namespace, value (in set), values and url (in repositories).

Examples:

repositories:
- name: your-private-git-repo-hosted-charts
  url: https://{{ requiredEnv "GITHUB_TOKEN"}}@raw.githubusercontent.com/kmzfs/helm-repo-in-github/master/

releases:
  - name: {{ requiredEnv "NAME" }}-vault
    namespace: {{ requiredEnv "NAME" }}
    chart: roboll/vault-secret-manager
    values:
      - db:
          username: {{ requiredEnv "DB_USERNAME" }}
          password: {{ requiredEnv "DB_PASSWORD" }}
    set:
      - name: proxy.domain
        value: {{ requiredEnv "PLATFORM_ID" }}.my-domain.com
      - name: proxy.scheme
        value: {{ env "SCHEME" | default "https" }}

installation

• download one of releases or
• run as a container or
• install from AUR for Archlinux or
• Windows (using scoop): scoop install helmfile
• macOS (using homebrew): brew install helmfile

getting started

Let's start with a simple helmfile and gradually improve it to fit your use-case!

Suppose the helmfile.yaml representing the desired state of your helm releases looks like:

releases:
- name: prom-norbac-ubuntu
  namespace: prometheus
  chart: stable/prometheus
  set:
  - name: rbac.create
    value: false

Sync your Kubernetes cluster state to the desired one by running:

helmfile apply

Congratulations! You now have your first Prometheus deployment running inside your cluster.

Iterate on the helmfile.yaml by referencing:

• Configuration syntax
• CLI reference.
• Helmfile Best Practices Guide

cli reference

NAME:
   helmfile -

USAGE:
   helmfile [global options] command [command options] [arguments...]

VERSION:
   v0.70.0

COMMANDS:
     deps      update charts based on the contents of requirements.yaml
     repos     sync repositories from state file (helm repo add && helm repo update)
     charts    DEPRECATED: sync releases from state file (helm upgrade --install)
     diff      diff releases from state file against env (helm diff)
     template  template releases from state file against env (helm template)
     lint      lint charts from state file (helm lint)
     sync      sync all resources from state file (repos, releases and chart deps)
     apply     apply all resources from state file only when there are changes
     status    retrieve status of releases in state file
     delete    DEPRECATED: delete releases from state file (helm delete)
     destroy   deletes and then purges releases
     test      test releases from state file (helm test)

GLOBAL OPTIONS:
   --helm-binary value, -b value           path to helm binary
   --file helmfile.yaml, -f helmfile.yaml  load config from file or directory. defaults to helmfile.yaml or `helmfile.d`(means `helmfile.d/*.yaml`) in this preference
   --environment default, -e default       specify the environment name. defaults to default
   --state-values-set value                set state values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)
   --state-values-file value               specify state values in a YAML file
   --quiet, -q                             Silence output. Equivalent to log-level warn
   --kube-context value                    Set kubectl context. Uses current context by default
   --log-level value                       Set log level, default info
   --namespace value, -n value             Set namespace. Uses the namespace set in the context by default, and is available in templates as {{ .Namespace }}
   --selector value, -l value              Only run using the releases that match labels. Labels can take the form of foo=bar or foo!=bar.
                                           A release must match all labels in a group in order to be used. Multiple groups can be specified at once.
                                           --selector tier=frontend,tier!=proxy --selector tier=backend. Will match all frontend, non-proxy releases AND all backend releases.
                                           The name of a release can be used as a label. --selector name=myrelease
   --allow-no-matching-release             Do not exit with an error code if the provided selector has no matching releases.
   --interactive, -i                       Request confirmation before attempting to modify clusters
   --help, -h                              show help
   --version, -v                           print the version

sync

The helmfile sync sub-command sync your cluster state as described in your helmfile. The default helmfile is helmfile.yaml, but any YAML file can be passed by specifying a --file path/to/your/yaml/file flag.

Under the covers, Helmfile executes helm upgrade --install for each release declared in the manifest, by optionally decrypting secrets to be consumed as helm chart values. It also updates specified chart repositories and updates the dependencies of any referenced local charts.

For Helm 2.9+ you can use a username and password to authenticate to a remote repository.

deps

The helmfile deps sub-command locks your helmfile state and local charts dependencies.

It basically runs helm dependency update on your helmfile state file and all the referenced local charts, so that you get a "lock" file per each helmfile state or local chart.

All the other helmfile sub-commands like sync use chart versions recorded in the lock files, so that e.g. untested chart versions won't suddenly get deployed to the production environment.

For example, the lock file for a helmfile state file named helmfile.1.yaml will be helmfile.1.lock. The lock file for a local chart would be requirements.lock, which is the same as helm.

It is recommended to version-control all the lock files, so that they can be used in the production deployment pipeline for extra reproducibility.

To bring in chart updates systematically, it would also be a good idea to run helmfile deps regularly, test it, and then update the lock files in the version-control system.

diff

The helmfile diff sub-command executes the helm-diff plugin across all of the charts/releases defined in the manifest.

To supply the diff functionality Helmfile needs the helm-diff plugin v2.9.0+1 or greater installed. For Helm 2.3+ you should be able to simply execute helm plugin install https://github.com/databus23/helm-diff. For more details please look at their documentation.

apply

The helmfile apply sub-command begins by executing diff. If diff finds that there is any changes, sync is executed. Adding --interactive instructs Helmfile to request your confirmation before sync.

An expected use-case of apply is to schedule it to run periodically, so that you can auto-fix skews between the desired and the current state of your apps running on Kubernetes clusters.

destroy

The helmfile destroy sub-command deletes and purges all the releases defined in the manifests.

helmfile --interactive destroy instructs Helmfile to request your confirmation before actually deleting releases.

destroy basically runs helm delete --purge on all the targeted releases. If you don't want purging, use helmfile delete instead.

delete (DEPRECATED)

The helmfile delete sub-command deletes all the releases defined in the manifests.

helmfile --interactive delete instructs Helmfile to request your confirmation before actually deleting releases.

Note that delete doesn't purge releases. So helmfile delete && helmfile sync results in sync failed due to that releases names are not deleted but preserved for future references. If you really want to remove releases for reuse, add --purge flag to run it like helmfile delete --purge.

secrets

The secrets parameter in a helmfile.yaml causes the helm-secrets plugin to be executed to decrypt the file.

To supply the secret functionality Helmfile needs the helm secrets plugin installed. For Helm 2.3+ you should be able to simply execute helm plugin install https://github.com/futuresimple/helm-secrets .

test

The helmfile test sub-command runs a helm test against specified releases in the manifest, default to all

Use --cleanup to delete pods upon completion.

lint

The helmfile lint sub-command runs a helm lint across all of the charts/releases defined in the manifest. Non local charts will be fetched into a temporary folder which will be deleted once the task is completed.

Paths Overview

Using manifest files in conjunction with command line argument can be a bit confusing.

A few rules to clear up this ambiguity:

• Absolute paths are always resolved as absolute paths
• Relative paths referenced in the Helmfile manifest itself are relative to that manifest
• Relative paths referenced on the command line are relative to the current working directory the user is in

For additional context, take a look at paths examples

Labels Overview

A selector can be used to only target a subset of releases when running Helmfile. This is useful for large helmfiles with releases that are logically grouped together.

Labels are simple key value pairs that are an optional field of the release spec. When selecting by label, the search can be inverted. tier!=backend would match all releases that do NOT have the tier: backend label. tier=fronted would only match releases with the tier: frontend label.

Multiple labels can be specified using , as a separator. A release must match all selectors in order to be selected for the final helm command.

The selector parameter can be specified multiple times. Each parameter is resolved independently so a release that matches any parameter will be used.

--selector tier=frontend --selector tier=backend will select all the charts

In addition to user supplied labels, the name, the namespace, and the chart are available to be used as selectors. The chart will just be the chart name excluding the repository (Example stable/filebeat would be selected using --selector chart=filebeat).

Templates

You can use go's text/template expressions in helmfile.yaml and values.yaml.gotmpl (templated helm values files). values.yaml references will be used verbatim. In other words:

• for value files ending with .gotmpl, template expressions will be rendered
• for plain value files (ending in .yaml), content will be used as-is

In addition to built-in ones, the following custom template functions are available:

• readFile reads the specified local file and generate a golang string
• fromYaml reads a golang string and generates a map
• setValueAtPath PATH NEW_VALUE traverses a golang map, replaces the value at the PATH with NEW_VALUE
• toYaml marshals a map into a string

Values Files Templates

You can reference a template of values file in your helmfile.yaml like below:

releases
- name: myapp
  chart: mychart
  values:
  - values.yaml.gotmpl

Every values file whose file extension is .gotmpl is considered as a template file.

Suppose values.yaml.gotmpl was something like:

{{ readFile "values.yaml" | fromYaml | setValueAtPath "foo.bar" "FOO_BAR" | toYaml }}

And values.yaml was:

foo:
  bar: ""

The resulting, temporary values.yaml that is generated from values.yaml.tpl would become:

foo:
  # Notice `setValueAtPath "foo.bar" "FOO_BAR"` in the template above
  bar: FOO_BAR

Refactoring helmfile.yaml with values files templates

One of expected use-cases of values files templates is to keep helmfile.yaml small and concise.

See the example helmfile.yaml below:

releases:
  - name: {{ requiredEnv "NAME" }}-vault
    namespace: {{ requiredEnv "NAME" }}
    chart: roboll/vault-secret-manager
    values:
      - db:
          username: {{ requiredEnv "DB_USERNAME" }}
          password: {{ requiredEnv "DB_PASSWORD" }}
    set:
      - name: proxy.domain
        value: {{ requiredEnv "PLATFORM_ID" }}.my-domain.com
      - name: proxy.scheme
        value: {{ env "SCHEME" | default "https" }}

The values and set sections of the config file can be separated out into a template:

helmfile.yaml:

releases:
  - name: {{ requiredEnv "NAME" }}-vault
    namespace: {{ requiredEnv "NAME" }}
    chart: roboll/vault-secret-manager
    values:
    - values.yaml.tmpl

values.yaml.tmpl:

db:
  username: {{ requiredEnv "DB_USERNAME" }}
  password: {{ requiredEnv "DB_PASSWORD" }}
proxy:
  domain: {{ requiredEnv "PLATFORM_ID" }}.my-domain.com
  scheme: {{ env "SCHEME" | default "https" }}

Environment

When you want to customize the contents of helmfile.yaml or values.yaml files per environment, use this feature.

You can define as many environments as you want under environments in helmfile.yaml.

The environment name defaults to default, that is, helmfile sync implies the default environment. The selected environment name can be referenced from helmfile.yaml and values.yaml.gotmpl by {{ .Environment.Name }}.

If you want to specify a non-default environment, provide a --environment NAME flag to helmfile like helmfile --environment production sync.

The below example shows how to define a production-only release:

environments:
  default:
  production:

releases:

{{ if eq .Environment.Name "production" }}
- name: newrelic-agent
  # snip
{{ end }}
- name: myapp
  # snip

Environment Values

Environment Values allows you to inject a set of values specific to the selected environment, into values.yaml templates. Use it to inject common values from the environment to multiple values files, to make your configuration DRY.

Suppose you have three files helmfile.yaml, production.yaml and values.yaml.gotmpl:

helmfile.yaml

environments:
  production:
    values:
    - production.yaml

releases:
- name: myapp
  values:
  - values.yaml.gotmpl

production.yaml

domain: prod.example.com
releaseName: prod

values.yaml.gotmpl

domain: {{ .Environment.Values | getOrNil "my.domain" | default "dev.example.com" }}

helmfile sync installs myapp with the value domain=dev.example.com, whereas helmfile --environment production sync installs the app with the value domain=production.example.com.

For even more flexibility, you can now use values declared in the environments: section in other parts of your helmfiles:

consider: default.yaml

domain: dev.example.com
releaseName: dev

environments:
  default:
    values:
    - default.yaml
  production:
    values:
    - production.yaml #  bare .yaml file, content will be used verbatim
    - other.yaml.gotmpl  #  template directives with potential side-effects like `exec` and `readFile` will be honoured

releases:
- name: myapp-{{ .Environment.Values.releaseName }} # release name will be one of `dev` or `prod` depending on selected environment
  values:
  - values.yaml.gotmpl

{{ if eq (.Environment.Values.releaseName "prod" ) }}
# this release would be installed only if selected environment is `production`
- name: production-specific-release
  ...
{{ end }}

Environment Secrets

Environment Secrets (not to be confused with Kubernetes Secrets) are encrypted versions of Environment Values. You can list any number of secrets.yaml files created using helm secrets or sops, so that Helmfile could automatically decrypt and merge the secrets into the environment values.

First you must have the helm-secrets plugin installed along with a .sops.yaml file to configure the method of encryption (this can be in the same directory as your helmfile or in the sub-directory containing your secrets files).

Then suppose you have a a foo.bar secret defined in environments/production/secrets.yaml:

foo.bar: "mysupersecretstring"

You can then encrypt it with helm secrets enc environments/production/secrets.yaml

Then reference that encrypted file in helmfile.yaml:

environments:
  production:
    secrets:
    - environments/production/secrets.yaml

releases:
- name: myapp
  chart: mychart
  values:
  - values.yaml.gotmpl

Then the environment secret foo.bar can be referenced by the below template expression in your values.yaml.gotmpl:

{{ .Environment.Values.foo.bar }}

Tillerless

With the helm-tiller plugin installed, you can work without tiller installed.

To enable this mode, you need to define tillerless: true and set the tillerNamespace in the helmDefaults section or in the releases entries.

Separating helmfile.yaml into multiple independent files

Once your helmfile.yaml got to contain too many releases, split it into multiple yaml files.

Recommended granularity of helmfile.yaml files is "per microservice" or "per team". And there are two ways to organize your files.

• Single directory
• Glob patterns

Single directory

helmfile -f path/to/directory loads and runs all the yaml files under the specified directory, each file as an independent helmfile.yaml. The default helmfile directory is helmfile.d, that is, in case helmfile is unable to locate helmfile.yaml, it tries to locate helmfile.d/*.yaml.

All the yaml files under the specified directory are processed in the alphabetical order. For example, you can use a <two digit number>-<microservice>.yaml naming convention to control the sync order.

• helmfile.d/
  • 00-database.yaml
  • 00-backend.yaml
  • 01-frontend.yaml

Glob patterns

In case you want more control over how multiple helmfile.yaml files are organized, use helmfiles: configuration key in the helmfile.yaml:

Suppose you have multiple microservices organized in a Git repository that looks like:

• myteam/ (sometimes it is equivalent to a k8s ns, that is kube-system for clusterops team)
  • apps/
    • filebeat/
      • helmfile.yaml (no charts/ exists, because it depends on the stable/filebeat chart hosted on the official helm charts repository)
      • README.md (each app managed by my team has a dedicated README maintained by the owners of the app)
    • metricbeat/
      • helmfile.yaml
      • README.md
    • elastalert-operator/
      • helmfile.yaml
      • README.md
      • charts/
        • elastalert-operator/
          • <the content of the local helm chart>

The benefits of this structure is that you can run git diff to locate in which directory=microservice a git commit has changes. It allows your CI system to run a workflow for the changed microservice only.

A downside of this is that you don't have an obvious way to sync all microservices at once. That is, you have to run:

for d in apps/*; do helmfile -f $d diff; if [ $? -eq 2 ]; then helmfile -f $d sync; fi; done

At this point, you'll start writing a Makefile under myteam/ so that make sync-all will do the job.

It does work, but you can rely on the Helmfile feature instead.

Put myteam/helmfile.yaml that looks like:

helmfiles:
- apps/*/helmfile.yaml

So that you can get rid of the Makefile and the bash snippet. Just run helmfile sync inside myteam/, and you are done.

All the files are sorted alphabetically per group = array item inside helmfiles:, so that you have granular control over ordering, too.

selectors

When composing helmfiles you can use selectors from the command line as well as explicit selectors inside the parent helmfile to filter the releases to be used.

helmfiles:
- apps/*/helmfile.yaml
- path: apps/a-helmfile.yaml
  selectors:          # list of selectors
  - name=prometheus
  - tier=frontend
- path: apps/b-helmfile.yaml # no selector, so all releases are used
selectors: []
- path: apps/c-helmfile.yaml # parent selector to be used or cli selector for the initial helmfile
  selectorsInherited: true

• When a selector is specified, only this selector applies and the parents or CLI selectors are ignored.
• When not selector is specified there are 2 modes for the selector inheritance because we would like to change the current inheritance behavior (see issue #344 ).
  • Legacy mode, sub-helmfiles without selectors inherit selectors from their parent helmfile. The initial helmfiles inherit from the command line selectors.
  • explicit mode, sub-helmfile without selectors do not inherit from their parent or the CLI selector. If you want them to inherit from their parent selector then use selectorsInherited: true. To enable this explicit mode you need to set the following environment variable HELMFILE_EXPERIMENTAL=explicit-selector-inheritance (see experimental).
• Using selector: [] will select all releases regardless of the parent selector or cli for the initial helmfile
• using selectorsInherited: true make the sub-helmfile selects releases with the parent selector or the cli for the initial helmfile. You cannot specify an explicit selector while using selectorsInherited: true

Importing values from any source

The exec template function that is available in values.yaml.gotmpl is useful for importing values from any source that is accessible by running a command:

A usual usage of exec would look like this:

mysetting: |
{{ exec "./mycmd" (list "arg1" "arg2" "--flag1") | indent 2 }}

Or even with a pipeline:

mysetting: |
{{ yourinput | exec "./mycmd-consume-stdin" (list "arg1" "arg2") | indent 2 }}

The possibility is endless. Try importing values from your golang app, bash script, jsonnet, or anything!

Hooks

A Helmfile hook is a per-release extension point that is composed of:

• events
• command
• args
• showlogs

Helmfile triggers various events while it is running. Once events are triggered, associated hooks are executed, by running the command with args. The standard output of the command will be displayed if showlogs is set and it's value is true.

Currently supported events are:

• prepare
• presync
• postsync
• cleanup

Hooks associated to prepare events are triggered after each release in your helmfile is loaded from YAML, before execution.

Hooks associated to cleanup events are triggered after each release is processed.

Hooks associated to presync events are triggered before each release is applied to the remote cluster. This is the ideal event to execute any commands that may mutate the cluster state as it will not be run for read-only operations like lint, diff or template.

Hooks associated to postsync events are triggered after each release is applied to the remote cluster. This is the ideal event to execute any commands that may mutate the cluster state as it will not be run for read-only operations like lint, diff or template.

The following is an example hook that just prints the contextual information provided to hook:

releases:
- name: myapp
  chart: mychart
  # *snip*
  hooks:
  - events: ["prepare", "cleanup"]
    showlogs: true
    command: "echo"
    args: ["{{`{{.Environment.Name}}`}}", "{{`{{.Release.Name}}`}}", "{{`{{.HelmfileCommand}}`}}\
"]

Let's say you ran helmfile --environment prod sync, the above hook results in executing:

echo {{Environment.Name}} {{.Release.Name}} {{.HelmfileCommand}}

Whereas the template expressions are executed thus the command becomes:

echo prod myapp sync

Now, replace echo with any command you like, and rewrite args that actually conforms to the command, so that you can integrate any command that does:

• templating
• linting
• testing

For templating, imagine that you created a hook that generates a helm chart on-the-fly by running an external tool like ksonnet, kustomize, or your own template engine. It will allow you to write your helm releases with any language you like, while still leveraging goodies provided by helm.

Helmfile + Kustomize

Do you prefer kustomize to write and organize your Kubernetes apps, but still want to leverage helm's useful features like rollback, history, and so on? This section is for you!

The combination of hooks and helmify-kustomize enables you to integrate kustomize into Helmfile.

That is, you can use kustommize to build a local helm chart from a kustomize overlay.

Let's assume you have a kustomize project named foo-kustomize like this:

foo-kustomize/
├── base
│   ├── configMap.yaml
│   ├── deployment.yaml
│   ├── kustomization.yaml
│   └── service.yaml
└── overlays
    ├── default
    │   ├── kustomization.yaml
    │   └── map.yaml
    ├── production
    │   ├── deployment.yaml
    │   └── kustomization.yaml
    └── staging
        ├── kustomization.yaml
        └── map.yaml

5 directories, 10 files

Write helmfile.yaml:

- name: kustomize
  chart: ./foo
  hooks:
  - events: ["prepare", "cleanup"]
    command: "../helmify"
    args: ["{{`{{if eq .Event.Name \"prepare\"}}build{{else}}clean{{end}}`}}", "{{`{{.Release.Ch\
art}}`}}", "{{`{{.Environment.Name}}`}}"]

Run helmfile --environment staging sync and see it results in helmfile running kustomize build foo-kustomize/overlays/staging > foo/templates/all.yaml.

Voilà! You can mix helm releases that are backed by remote charts, local charts, and even kustomize overlays.

Guides

Use the Helmfile Best Practices Guide to write advanced helmfiles that feature:

• Default values
• Layering

We also have dedicated documentation on the following topics which might interest you:

• Shared Configurations Across Teams

Or join our friendly slack community in the #helmfile channel to ask questions and get help. Check out our slack archive for good examples of how others are using it.

Using env files

Helmfile itself doesn't have an ability to load env files. But you can write some bash script to achieve the goal:

set -a; . .env; set +a; helmfile sync

Please see #203 for more context.

Running helmfile interactively

helmfile --interactive [apply|destroy] requests confirmation from you before actually modifying your cluster.

Use it when you're running helmfile manually on your local machine or a kind of secure administrative hosts.

For your local use-case, aliasing it like alias hi='helmfile --interactive' would be convenient.

Running Helmfile without an Internet connection

Once you download all required charts into your machine, you can run helmfile charts to deploy your apps. It basically run only helm upgrade --install with your already-downloaded charts, hence no Internet connection is required. See #155 for more information on this topic.

Experimental features

Some experimental features may be available for testing in perspective of being (or not) included in a future release. Those features are set using the environment variable HELMFILE_EXPERIMENTAL. Here is the current experimental feature :

• explicit-selector-inheritance : remove today implicit cli selectors inheritance for composed helmfiles, see composition selector

If you want to enable all experimental features set the env var to HELMFILE_EXPERIMENTAL=true

Examples

For more examples, see the examples/README.md or the helmfile distribution by Cloud Posse.

Attribution

We use:

• semtag for automated semver tagging. I greatly appreciate the author(pnikosis)'s effort on creating it and their kindness to share it!