logger injector

Operator that run into K8s cluster level or outside looking into pods that match some annotations and inject a sidecar fluentd container to push the app level logs to Elastic search

workflow workflow



How it works

The injector run on cluster level and watch all objects changes and if it contains special annotations the inector start modify the deployment or stateful pod to add fluentd side-car containers configured to look into the pod logs volume and stream the logs to elastic search


  • automatic Injector (fluentd sidecar container)
  • You do not need to configure anything to your app just write your logs into volume
  • Support multiple worker threads
  • One time installation per cluster
  • support in-cluster configuration or kube config if you need to run it outside K8s cluster

Tech Stack

  • Go

Supported K8s workloads

  • Deployment
  • Stateful
  • DaemonSet
  • Job
  • Cron Job


  • Add more option to control elastic search and file formats
  • Support replication
  • Handle multiple streamer more than elastic search

Injector Configurations

Variable Type Description
ELASTIC_HOST string elastic search host
ELASTIC_PORT number elastic search port
ELASTIC_PASSWORD number elastic user password
ELASTIC_USER string elastic user
ELASTIC_SSL_VERIFY boolean elastic skip ssl verify default false
ELASTIC_SCHEME string elastic http/https default https
ELASTIC_SSL_VERSION string elastic tls version default TLSv1_2
FLUENTD_IMAGE_REPOSITORY string fluentd image default fluent/fluentd-kubernetes-daemonset:v1-debian-elasticsearch
IN_CLUSTER_CONFIG boolean Set it true if the app will run inside the cluster

App required annotations

name type Description
logger.injector.io/agent-inject boolean Required to be true
logger.injector.io/log-tag-name string Elastic search tag for create index
logger.injector.io/flush-interval string Fluentd flush interval default 1m
logger.injector.io/flush-interval string Fluentd flush interval default 1m
logger.injector.io/log-path-pattern string Your log file pattern such as log*.txt default log*.log
logger.injector.io/storage-class-name string Storage class Name to create PVC for fluentd buffer default emptyDir{}
logger.injector.io/fluentd-vol-size string Volume storage for fluentd buffer PV default 1 Gi

How to install

In cluster setup

  • Open bin directory and copy default.properties to the bin dir and populate your environment variables value
  • run deploy.sh

Docker stand-alone

  • create .env file from default.properties
  • populate all required environment variables
  • Make sure you have docker-compose
  • Make sure you have config file inside ~/.kube/ in your host machine
  • Run docker-compose up --build -d


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