sysincz/k8s-sidecar-cm-to-file repository overview

⁠What?

Fork from kiwigrid/k8s-sidecar https://github.com/kiwigrid/k8s-sidecar⁠

This is a docker container intended to run inside a kubernetes cluster to collect config maps with a specified label and store the included files in an local folder. It can also send a html request to a specified URL after a configmap change. The main target is to be run as a sidecar container to supply an application with information from the cluster. The contained python script is working with the Kubernetes API 1.10

⁠Schema

⁠Labels

⁠Why?

Currently there is no simple way to hand files in configmaps to a service and keep them updated during runtime.

⁠How?

Run the container created by this repo together you application in an single pod with a shared volume. Specify which label should be monitored and where the files should be stored. By adding additional env variables the container can send a html request to specified URL.

⁠Features

• Extract files from config maps
• Filter based on label
• Update/Delete on change of configmap
• Marge configmaps data to one file

⁠Usage

Example for a simple deployment can be found in example.yaml. Depending on the cluster setup you have to grant yourself admin rights first: kubectl create clusterrolebinding cluster-admin-binding --clusterrole cluster-admin --user $(gcloud config get-value account)

⁠Tags

• Prometheus
• Alertmanager config
• amtool check-config alertmanager.yaml
• ConfigMaps
• Grafana Dashboards big file
• Multi Teams
• Cross Namespace
• Files to secret
• alertmanager.yaml to secrets

⁠Configuration Environment Variables

• LABEL

  • description: Label that should be used for filtering
  • required: true
  • type: string

• FOLDER

  • description: Folder where the files should be placed
  • required: true
  • type: string

• NAMESPACE

  • description: If specified, the sidecar will search for config-maps inside this namespace. Otherwise the namespace in which the sidecar is running will be used. It's also possible to specify ALL to search in all namespaces.
  • required: false
  • type: string

• REQ_URL

  • description: URL to which send a request after a configmap got reloaded
  • required: false
  • type: URI

• REQ_METHOD

  • description: Request method GET(default) or POST
  • required: false
  • type: string

• REQ_PAYLOAD

  • description: If you use POST you can also provide json payload
  • required: false
  • type: json

• TIMEOUT

  • description: Auto reconnect to kubernetes after ..sec [ bug fix when sidecar and kubernetes api stoped communicate ]
  • required: false
  • type: int
  • default: "600"

⁠Configuration Environment Variables For Part

• PARTFILES

  • description: Take the files with the '.parts\d+' in name of file and save it in one file
  • default: False
  • required: false
  • type: boolean

• COMMENT

  • description: Place comment with informtation about datasource to destination file
  • default: True
  • required: false
  • type: boolean

• COMMAND_AFTER_CC

  • description: Command after success check config
  • required: false
  • type: string
  • example: "python ./files_to_cm.py --name=alertmanager-main --dir /tmp/k8s_sidecar-cm-to-file/ --file_pattern '.*.yaml'"

⁠Configuration Environment Variables For Part check config amtool (PARTFILES=True)

• CHECK_CONFIG_COMMAND

  • description: Command for check config
  • required: false
  • type: string
  • example value: "./amtool check-config /tmp/k8s_sidecar-cm-to-file/alertmanager.yaml"

• OK_EXIT_CODES

  • description: Acceptable exit codes from command CHECK_CONFIG_COMMAND
  • default: 0,127
  • required: false
  • type: string
  • example value: "0,127"

⁠Configuration Environment Variables For Part Files Mapping (PARTFILES=True)

• DATA_NAME_{somename} example: DATA_NAME_ROUTE

  • description: Name of file in ConfigMap
  • required: false
  • type: string
  • example value: "alertmanager-route"

• DATA_FILE_{somename} example: DATA_FILE_ROUTE

  • description: Destination file where will be inserted data from ConfigMap "DATA_NAME_{somename}"
  • required: false (true if DATA_NAME_{somename} is set )
  • type: string
  • example value: "alertmanager.yaml.part1.01routes"

• DATA_INDENT_{somename} example: DATA_INDENT_ROUTE

  • description: Count of spaces on left side of strig before save data to "DATA_FILE_{somename}"
  • default: 0
  • required: false
  • type: int
  • example value: "2"

⁠file to secrets

# python ./files_to_cm.py -h
usage: ./files_to_cm.py [-h] --name NAME --dir DIR
                        [--file_pattern FILE_PATTERN] [--namespace NAMESPACE]

optional arguments:
  -h, --help            show this help message and exit
  --name NAME           Name of Secret/Configmap
  --dir DIR             Source directory path
  --file_pattern FILE_PATTERN
                        File pattern for match files (default: '.*')
  --namespace NAMESPACE
                        Name of Namespace

example: Script take all yaml files from directory /tmp/k8s_sidecar-cm-to-file/ and create secret with name alertmanager-main in namespace default python ./files_to_cm.py --name=alertmanager-main --dir /tmp/k8s_sidecar-cm-to-file/ --file_pattern '.*.yaml' --namespace 'default'

For this step you need have set up ClusterRole

- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get", "watch", "list","create","update"]