kubectl productivity

Posted by Manish Panchmatia on Thursday, December 5, 2019 Labels: , , , / Comments: (0)

Auto Complete

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Context 

kubectx helps you switch between clusters back and forth:

kubens helps you switch between Kubernetes namespaces smoothly:


Explain

kubectl explain
command outputs the specification of the requested resource or field.

Alias

A script to generate hundreds of convenient kubectl aliases programmatically.


Syntax explanation
  • k=kubectl
    • sys=--namespace kube-system
  • commands:
    • g=get
    • d=describe
    • rm=delete
    • a:apply -f
    • ex: exec -i -t
    • lo: logs -f
  • resources:
    • po=pod, dep=deployment, ing=ingress, svc=service, cm=configmap, sec=secret, ns=namespace, no=node
  • flags:
    • output format: oyaml, ojson, owide
    • all: --all or --all-namespaces depending on the command
    • sl: --show-labels
    • w=-w/--watch
  • value flags (should be at the end):
    • n=-n/--namespace
    • f=-f/--filename
    • l=-l/--selector

Reference

eBPF, OPA, Blackbox exporter, ffwd, Heroic

Posted by Manish Panchmatia Labels: , , / Comments: (0)

eBPF can be used for 

 1. Map application and HA architecture
2. Detect network issues
3. Identify misbehaving svc

 https://www.youtube.com/watch?v=thBCB7YeZ2g&list=PLj6h78yzYM2NDs-iu8WU5fMxINxHXlien&index=3

 Open Policy Agent https://github.com/open-policy-agent/opa can be used to validate CRD
https://www.youtube.com/watch?v=DUe_8nf42Ik&list=PLj6h78yzYM2NDs-iu8WU5fMxINxHXlien&index=5

 The blackbox exporter allows blackbox probing of endpoints over HTTP, HTTPS, DNS, TCP and ICMP. https://github.com/prometheus/blackbox_exporter

 ffwd is a flexible metric forwarding agent. It is intended to run locally on the system and receive metrics through a wide set of protocols and then forward them to your TSDB.  https://github.com/spotify/ffwd 

 Heroic A scalable time series database based on Bigtable, Cassandra, and Elasticsearch. https://github.com/spotify/heroic

 https://www.youtube.com/watch?v=AA8e5v43AcU&list=PLj6h78yzYM2NDs-iu8WU5fMxINxHXlien&index=6

Easily Observing Operators

Posted by Manish Panchmatia Labels: , , / Comments: (0)

kube-state-metrics you can gather the following state about your cluster:
  • Counts of each object type
  • All of the Kubernetes labels and their values attached to each object
  • The creation time (as an epoch) of each object
  • Some generic, object specific “info”
  • Other states specific to the object in question

kube-state-metrics can be deployed like a classic Kubernetes service with only one replica.


List of metrics


Metrics about your CRD


Kustomize plugins

Posted by Manish Panchmatia Labels: , , / Comments: (0)

This is the third article out of three articles on Kubernetes tool : Kustomize. This article covers the plugins. 

 kustomize plugins

 Kustomize offers a plugin framework allowing people to write their own resource generators and transformers.

 kustomization.yaml

 generators:
- gen_file.yaml
transformers:
- trans_file.yaml

 Let's focus on gen_file. Trans_file will be similar. 

gen_file.yaml

 apiVersion: "apiVersion"
kind: Gen_File
metadata:
  name: "some name"

 Now the file name "Gen_File" will be searched at path  
XDG_CONFIG_HOME = $HOME/.config = /home/manish.config
/home/manish/.config/kustomize/plugin/${apiVersion}/LOWERCASE(${kind})
Possible value for apiVersion = someteam.example.com/v1

 If failed then "Gen_File.so" will be searched at same path

 This file will be invoked with gen_file.yaml

 Reference : https://github.com/kubernetes-sigs/kustomize/tree/master/docs/plugins

 Built-in plugins : https://github.com/kubernetes-sigs/kustomize/tree/master/plugin/builtin
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/chart.md
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/secretGeneratorPlugin.md
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/goGetterGeneratorPlugin.md
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/validationTransformer/README.md
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/transformerconfigs/README.md

 Plugin Development
https://github.com/kubernetes-sigs/kustomize/blob/master/docs/plugins/execPluginGuidedExample.md
https://github.com/kubernetes-sigs/kustomize/blob/master/docs/plugins/goPluginGuidedExample.md

UseCases of Kustomize

Posted by Manish Panchmatia Labels: , , / Comments: (0)

This is the second article out of three articles on Kubernetes tool : Kustomize. This article covers the usecases. 

 ==============================
UseCase 1 : Config map generation and secreat generation 
secretGenerator:
- name: myregistrykey
 type: docker-registry
 literals:
 - docker-server=DOCKER_REGISTRY_SERVER
 - docker-username=DOCKER_USER
 - docker-password=DOCKER_PASSWORD
 - docker-email=DOCKER_EMAIL


 This is same as: 

 kubectl create secret docker-registry myregistrykey --docker-server=DOCKER_REGISTRY_SERVER --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL

 Same as above configMapGenerator

 configMapGenerator
- name: profile
  files: 
  - hello.config
  
  
We can also merge two configmaps

 configMapGenerator:
- name: my-configmap
  behavior: merge
  files:
  - plumbing.properties
  - secret.properties


 Configmap from literals

 configMapGenerator:
- name: my-configmap
  literals:
  - foo=bar
  - baz=qux
  
==============================
UseCase 2 : Creating multiple variants using overlays. 
Edit attributes  as per specific file. Here localserv.yaml . Keyword is patchesStrategicMerge

 kustomize edit add patch ocalserv.yaml

 bases:
- ../../base
patchesStrategicMerge:
- localserv.yaml

 Multi Variant Examples: 
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/helloWorld/README.md
https://github.com/kubernetes-sigs/kustomize/blob/master/examples/breakfast.md

 we can use "kustomize diff base/variant1/variant2" command to see the difference. 

 ==============================
UseCase 3 : edit container image and tag

 kustomize edit set image busybox=alpine:3.6
images:
- name: busybox
  newName: alpine
  newTag: 3.6
==============================
UseCase 4 : Remote Target
kustomize build can be run on a URL.

 The effect is the same as cloning the repo, checking out a particular ref (commit hash, branch name, release tag, etc.), then running kustomize build against the desired directory in the local copy.
==============================
UseCase 5 : applying a JSON patch. Replace and add

 cat <$DEMO_HOME/ingress_patch.json
[
  {"op": "replace", "path": "/spec/rules/0/host", "value": "foo.bar.io"},
  {"op": "replace", "path": "/spec/rules/0/http/paths/0/backend/servicePort", "value": 8080}
]
EOF
You can also write the patch in YAML format. This example also shows the "add" operation:

 cat <$DEMO_HOME/ingress_patch.yaml
- op: replace
  path: /spec/rules/0/host
  value: foo.bar.io

 - op: add
  path: /spec/rules/0/http/paths/-
  value:
    path: '/test'
    backend:
      serviceName: my-test
      servicePort: 8081
EOF
patchesJson6902:
- target:
    group: apps
    version: v1
    kind: Deployment
    name: my-nginx
  path: patch.yaml
==============================
UseCase 6 : Patch on multiple objects
JSON patch and strategic merge patch can be applied to selected resources

 patches:
- path: "PatchFile"
  target:
    group: "Group"
    version: "Version"
    kind: "Kind"
    name: "Name"
    namespace: "Namespace"
    labelSelector: "LabelSelector"
    annotationSelector: "AnnotationSelector"
==============================
UseCase 7 : Injecting k8s runtime data into containers

https://github.com/kubernetes-sigs/kustomize/blob/master/examples/wordpress/README.md