K8s helm

What is Helm
git
Helm is a tool for managing Charts. Charts are packages of pre-configured Kubernetes resources.
Helm - apt
Charts - debian package

package manager
templating engine
release manager

history

Best Practice
summary
details

Helm concepts
Helm is organized around several key concepts:
A chart is a package of pre-configured Kubernetes resources
A release is a specific instance of a chart which has been deployed to the cluster using Helm
A repository is a group of published charts which can be made available to others

Helm components(helm2)

• Helm Client - allows developers to create new charts, manage chart repositories, and interact with the tiller server.
• Tiller Server - runs inside the Kubernetes cluster. Interacts with Helm client, and translates chart definitions and configuration to Kubernetes API commands. Tiller combines a chart and its configuration to build a release. Tiller is also responsible for upgrading charts, or uninstalling and deleting them from the Kubernetes cluster.

Helm in Kubernetes
(°0°)

Example
refer
charts

what-the-helm
├── Chart.yaml 
├── charts
├── templates
│   ├── NOTES.txt
│   ├── _helpers.tpl
│   ├── deployment.yaml
│   ├── ingress.yaml
│   ├── service.yaml
│   └── tests
│       └── test-connection.yaml
└── values.yaml

Chart.yaml - the metadata for your Helm Chart.
values.yaml - values that can be used as variables in your templates.
templates/*.yaml - Example Kubernetes manifests.
_helpers.tpl - helper functions that can be used inside the templates.
templates/NOTES.txt - templated notes that are displayed on Chart install.

helm install --values=my-values.yaml <chartname>
helm install --set version=2.0.0

Helm chart testing(WIP)

Helm chart production

Release Management

• helm install
• helm upgrade --> changes are applied to existing deployment instead of creating a new one
• helm rollback --> handling rollbacks

Helmfile
repo
a helm for helm, helmfile is used to deploy collections of charts.
helmfile.yaml is a declarative configuration file that makes it easier to deploy and manage a large number of helm charts.

demo

root
├── environments
│   ├── commons.yaml
│   │
│   ├── development
│   │   ├── charts.yaml
│   │   ├── kafka.yaml
│   │   ├── magic-ns.yaml
│   │   ├── nginx-ingress-internal.yaml
│   │   ├── nginx-ingress-public.yaml
│   │   └── zookeeper.yaml
│   │
│   └── staging
│       ├── charts.yaml
│       ├── magic-ns.yaml.gotmpl
│       ├── nginx-ingress-internal.yaml.gotmpl
│       └── nginx-ingress-public.yaml.gotmpl
│
└── helmfile.d - Read about single directory
    ├── 00-init.yaml
    ├── 01-infra.yaml
    ├── 02-db.yaml
    ├── 03-backend.yaml
    └── 04-data.yaml

helm secrets

1. helm plugin https://github.com/futuresimple/helm-secrets
2. PGP to generate key pair(read from vault)
3. create .sops.yaml with fingerprint

   creation_rules:
    -pgp:"9B08 DC57 18C3 8BA1 160D  EE53 4115 C1D9 D94B D9B2"
   

4. create a file secrets and encrypt

   helm secrets enc secrets.yaml
   

5. decrypt

   helm secrets dec values.yaml
   

   spinnaker access

6. spinnaker is running on a k8s cluster
7. other clusters kubeconfig are stored in that cluster as secrets, or using S3 on cloud

   kubectl create secret generic --from-file=$HOME/.kube/config my-kubeconfig
   kubeConfig:
     enabled: true
     secretName: my-kubeconfig
     secretKey: config
     contexts:
     # Names of contexts available in the uploaded kubeconfig
     - my-context
     # This is the context from the list above that you would like
     # to deploy Spinnaker itself to.
     deploymentContext: my-context
   

   Halyard BOM

8. Spinnaker uses a Bill of Materials to describe the services that are part of a release.
9. Halyard is a tool for configuring, installing, and updating Spinnaker, similar to helm

   ├── bom-yaml-1.19.4.tar.gz   ## bom yaml files
   ├── halyard.sh               ## halyard init script
   ├── halyard.yaml             ## halyard config
   ├── ingress.yaml             ## spinnaker ingress
   └── install.sh               ## install
   

vs kustomize

	                  Kustomize	  Helm
Method of operation	overlays	templating
Ease of use	simple	complex
Support for packaging	no	yes
Native kubectl integration	yes	no
Declarative/ imperative	declarative	imperative