Best Practice

• https://www.openshift.com/blog/kubernetes-operators-best-practices

Base Concept

• https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/
• https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/
• https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definition-versioning/

Without help of kubebuilder

• https://itnext.io/how-to-create-a-kubernetes-custom-controller-using-client-go-f36a7a7536cc
• https://itnext.io/how-to-generate-client-codes-for-kubernetes-custom-resource-definitions-crd-b4b9907769ba

Approches

• https://www.martin-helmich.de/en/blog/kubernetes-crd-client.html
• https://medium.com/@trstringer/create-kubernetes-controllers-for-core-and-custom-resources-62fc35ad64a3
• https://itnext.io/how-to-create-a-kubernetes-custom-controller-using-client-go-f36a7a7536cc
• https://itnext.io/building-an-operator-for-kubernetes-with-the-sample-controller-b4204be9ad56
• https://itnext.io/building-an-operator-for-kubernetes-with-kubebuilder-17cbd3f07761
• https://itnext.io/building-an-operator-for-kubernetes-with-operator-sdk-40a029ea056
• https://medium.com/@cloudark/kubernetes-custom-controllers-b6c7d0668fdf
• https://engineering.bitnami.com/articles/a-deep-dive-into-kubernetes-controllers.html
• https://engineering.bitnami.com/articles/kubewatch-an-example-of-kubernetes-custom-controller.html
• https://haojianxun.github.io/2018/11/10/kubernetes%20CRD%E4%B8%8B%E7%AF%87--%E7%BC%96%E5%86%99%E8%87%AA%E5%AE%9A%E4%B9%89%E6%8E%A7%E5%88%B6%E5%99%A8/

Source Code Anylsis

• https://www.kubernetes.org.cn/5344.html

code-generator

• https://blog.openshift.com/kubernetes-deep-dive-code-generation-customresources/ [必读]
• https://itnext.io/how-to-generate-client-codes-for-kubernetes-custom-resource-definitions-crd-b4b9907769ba

• https://kubernetes.io/docs/concepts/configuration/taint-and-toleration/

https://www.elastic.co/guide/en/elasticsearch/reference/7.6/overview-index-lifecycle-management.html
You can create and apply Index lifecycle management (ILM) policies to automatically manage your indices according to your performance, resiliency, and retention requirements. Index lifecycle policies can trigger actions such as:
- Rollover - Redirect an alias to begin writing to a new index when the existing index reaches a certain age, number of docs, or size.
- Shrink - Reduce the number of primary shards in an index.
- Force merge - Manually trigger a merge to reduce the number of segments in each shard of an index and free up the space used by deleted documents.
- Freeze - Make an index read-only and minimize its memory footprint.
- Delete - Permanently remove an index, including all of its data and metadata.

• 冷热数据分离 https://www.elastic.co/cn/blog/implementing-hot-warm-cold-in-elasticsearch-with-index-lifecycle-management
• auto rollover https://www.elastic.co/guide/en/elasticsearch/reference/7.6/getting-started-index-lifecycle-management.html

• https://www.elastic.co/cn/blog/implementing-hot-warm-cold-in-elasticsearch-with-index-lifecycle-management

• cobra
• viper
• strings
• goqu
• Golang plugin
• go-restful

• https://www.docker.com/blog/getting-started-with-docker-for-arm-on-linux/
• https://www.stereolabs.com/docs/docker/building-arm-container-on-x86/
• https://www.docker.com/blog/multi-arch-images/
• treasure-data/omnibus-td-agent#209

https://github.com/spf13/viper

• https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/
• https://semaphoreci.com/community/tutorials/building-go-web-applications-and-microservices-using-gin

https://github.com/spf13/cobra

• https://docs.openshift.com/container-platform/4.3/authentication/managing-security-context-constraints.html
• https://kubernetes.io/docs/concepts/policy/pod-security-policy/
• https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

Oauth

• http://www.ruanyifeng.com/blog/2014/05/oauth_2_0.html
• https://www.digitalocean.com/community/tutorials/an-introduction-to-oauth-2

OIDC

• https://developer.okta.com/blog/2017/07/25/oidc-primer-part-1
• https://developer.okta.com/blog/2017/07/25/oidc-primer-part-2
• https://developer.okta.com/blog/2017/08/01/oidc-primer-part-3

Other

• https://medium.com/@mrbobbytables/kubernetes-day-2-operations-authn-authz-with-oidc-and-a-little-help-from-keycloak-de4ea1bdbbe

V2

• https://helm.sh/docs/intro/using_helm/
• https://github.com/RehanSaeed/Helm-Cheat-Sheet

• https://kubernetes.io/docs/concepts/configuration/secret/
• https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/
• https://kubernetes.io/docs/tutorials/configuration/configure-redis-using-configmap/

• https://www.elastic.co/cn/blog/follow-the-leader-an-introduction-to-cross-cluster-replication-in-elasticsearch
• https://www.elastic.co/cn/blog/cross-datacenter-replication-with-elasticsearch-cross-cluster-replication
• https://www.elastic.co/guide/en/elasticsearch/reference/6.7/ccr-overview.html
• https://www.elastic.co/guide/en/elasticsearch/reference/6.7/ccr-getting-started.html
• https://www.elastic.co/guide/en/elasticsearch/reference/6.7/ccr-put-auto-follow-pattern.html

https://medium.com/faun/intro-to-kubebuilder-how-to-guide-for-building-custom-kubernetes-apis-using-crds-operators-6b8213f6dcc4

https://golang.org/pkg/encoding/json/
https://golang.org/pkg/encoding/xml/

• Add new secret for pull
• Add imagePullSecrets in pod manifest

first login, then create the secret

docker login <url>

cat ~/.docker/config.json

kubectl create secret generic <name> --from-file=.dockerconfigjson=/root/.docker/config.json --type=kubernetes.io/dockerconfigjson -n <ns-name>

create secret with command line opts

kubectl create secret docker-registry regcred --docker-server=<your-registry-server> --docker-username=<your-name> --docker-password=<your-pword> --docker-email=<your-email>

https://kubernetes.io/docs/concepts/overview/components/
https://kubernetes.io/blog/2018/01/introducing-client-go-version-6/

https://kubesphere.io/docs/toolbox/log-query/

The logs of applications and systems can help you better understand what is happening inside your cluster and workloads. The logs are particularly useful for debugging problems and monitoring cluster activities. KubeSphere provides a powerful and easy-to-use logging system which offers users the capabilities of log collection, query and management from the perspective of tenants. The tenant-based logging system is much more useful than Kibana since different tenants can only view their own logs, leading to better security. Moreover, KubeSphere logging system filters out some redundant information so that tenants can only focus on logs that are useful to them.

https://github.com/doug-martin/goqu

Recover发生的场景

Recovery automatically occurs during the following processes:

• Node startup or failure. This type of recovery is called a local store recovery.
• Primary shard replication.
• Relocation of a shard to a different node in the same cluster.
• Snapshot restoration.

查看分片失败原因

GET _cluster/allocation/explain
{
  "index": "log-20200512",
  "shard": 4,
  "primary": true
}

尝试为失败的分片重新分配节点

POST _cluster/rerouter?retry_failed

学习Golang中常用字符串操作，可以结合Python中字符串进行对比学习

https://golang.org/pkg/plugin/

github.com/emicklei/go-restful
net/http

ES index templates可以设置：

• index_patterns
• settings
• mappings
• aliases

References

Openssl

• https://www.digitalocean.com/community/tutorials/openssl-essentials-working-with-ssl-certificates-private-keys-and-csrs
• https://www.keycdn.com/blog/openssl-tutorial

Keytool

• https://www.digitalocean.com/community/tutorials/java-keytool-essentials-working-with-java-keystores
• http://tutorials.jenkov.com/java-cryptography/keytool.html

https://tour.golang.org/moretypes/1