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Installing Sematext Agent on Docker

Installing Sematext Agent can be done by using Docker, Docker Compose, and Docker Swarm / Enterprise.

Docker¶

To deploy the Sematext Agent as a container, run the following command on each host:

docker run -d  --restart always --privileged -P --name st-agent \
-v /:/hostfs:ro \
-v /sys/:/hostfs/sys:ro \
-v /var/run/:/var/run/ \
-v /sys/kernel/debug:/sys/kernel/debug \
-v /etc/passwd:/etc/passwd:ro \
-v /etc/group:/etc/group:ro \
-e INFRA_TOKEN=<YOUR_INFRA_APP_TOKEN_HERE> \
-e REGION=<US or EU> \
sematext/agent:latest

Read more about why Sematext Agent needs access to host files and directories.

Besides providing several bind mounts for Docker socket, procfs and journal directory, App tokens are required to ship data to the appropriate Monitoring Apps. Sematext Agent will gather data about running processes on the system, basic operating system metrics, machine/instance related information, and ship it to the Infra App token. It will also detect active containers and start collecting different container metrics such as memory usage, network I/O statistics, disk throughput, etc.

By default, the US region receiver endpoints are used to ship data to Sematext Cloud. You can override receiver addresses by either passing SERVER_BASE_URL for metrics receivers, LOGS_RECEIVER_URL and EVENTS_RECEIVER_URL for log and event receivers respectively or specify an alternative (EU) region via REGION environment variable.

Note that if any of the *_URL environment variables are set, region specific receiver endpoints are ignored.

Docker for OSX¶

To deploy the Sematext Agent on Docker for OSX, run the following command:

docker run -d  --restart always --privileged -P --name st-agent \
-v /:/hostfs:ro \
-v /sys/:/hostfs/sys:ro \
-v /var/run/:/var/run/ \
-v /sys/kernel/debug:/sys/kernel/debug \
-v /etc/passwd:/etc/passwd:ro \
-v /etc/group:/etc/group:ro \
-v /var/run/docker.sock:/var/run/docker.sock:ro \
-e INFRA_TOKEN=<YOUR_INFRA_APP_TOKEN_HERE> \
-e REGION=<US or EU> \
sematext/agent:latest

Docker on OSX relies on virtualization capabilities to spawn the containers inside the VM. The side effect is that Sematext Agent will report the OS metrics of the VM box and not the bare-metal machine where the OSX is running.

Run Sematext Agent with a Config File¶

Mount the configuration file into the container and set the path to the configuration file -v /opt/st-agent/st-agent.yml:/opt/st-agent/st-agent.yml via CONFIG_FILE environment variable.

$ docker run -d  --restart always --privileged -P --name st-agent \
-v /:/hostfs:ro \
-v /sys/:/hostfs/sys:ro \
-v /var/run/:/var/run/ \
-v /sys/kernel/debug:/sys/kernel/debug \
-v /etc/passwd:/etc/passwd:ro \
-v /etc/group:/etc/group:ro \
-v /dev:/hostfs/dev:ro \
-e INFRA_TOKEN=<YOUR_INFRA_APP_TOKEN_HERE> \
-e REGION=<US or EU> \
sematext/agent:latest

Docker Compose¶

For the deployments that are orchestrated by Docker Compose, you can use the following manifest:

# docker-compose.yml
version: '3'
services:
  sematext-agent:
    image: 'sematext/agent:latest'
    environment:
      - affinity:container!=*sematext-agent*
      - INFRA_TOKEN=<YOUR_INFRA_APP_TOKEN_HERE>
      - REGION=<US or EU>
      - LOGGING_WRITE_EVENTS=false
      - LOGGING_REQUEST_TRACKING=false
      - LOGGING_LEVEL=info
      - NODE_NAME=$HOSTNAME
      - CONTAINER_SKIP_BY_IMAGE=sematext
    cap_add:
      - SYS_ADMIN
    restart: always
    volumes:
      - '/:/hostfs:ro'
      - '/etc/passwd:/etc/passwd:ro'
      - '/etc/group:/etc/group:ro'
      - '/var/run/:/var/run/'
      - '/sys/kernel/debug:/sys/kernel/debug'
      - '/sys:/host/sys:ro'
      - '/dev:/hostfs/dev:ro'

Docker Swarm / Enterprise¶

Create an Infra Monitoring App in Sematext and follow the instructions in the UI.

The Swarm network has to be created only if you're deploying the agent with docker service command. On the contrary, if you're using the docker stack deploy command and using the docker-compose.yml descriptor, it is not necessary to create the agent network.

docker network create -d overlay --attachable --scope=swarm st-agent-net

After that, Sematext Agent can be deployed as a global service on all Swarm nodes with a single command:

docker service create --mode global --network st-agent-net \
--name st-agent \
--restart-condition any \
--mount type=bind,src=/,dst=/hostfs,readonly \
--mount type=bind,src=/etc/passwd,dst=/etc/passwd,readonly \
--mount type=bind,src=/etc/group,dst=/etc/group,readonly \
--mount type=bind,src=/var/run,dst=/var/run/ \
--mount type=bind,src=/sys/kernel/debug,dst=/sys/kernel/debug \
--mount type=bind,src=/sys,dst=/host/sys,readonly \
--mount type=bind,src=/dev,dst=/hostfs/dev,readonly \
-e INFRA_TOKEN=<YOUR_INFRA_APP_TOKEN_HERE> \
-e REGION=<US or EU> \
sematext/agent:latest

If you like using docker stack, the following docker-compose.yml provides a working configuration:

version: "3"
services:
  st-agent:
    image: sematext/agent:latest
    environment:
      INFRA_TOKEN: <YOUR_INFRA_APP_TOKEN_HERE>
      REGION: <US or EU>
    deploy:
      mode: global
      restart_policy:
        condition: any
    volumes:
    - type: bind
      source: /
      target: /hostfs
      read_only: true
    - type: bind
      source: /etc/passwd
      target: /etc/passwd
      read_only: true
    - type: bind
      source: /etc/group
      target: /etc/group
      read_only: true
    - type: bind
      source: /var/run
      target: /var/run/
    - type: bind
      source: /sys/kernel/debug
      target: /sys/kernel/debug
    - type: bind
      source: /sys
      target: /host/sys
      read_only: true
    - type: bind
      source: /dev
      target: /hostfs/dev
      read_only: true
networks:
  default:
    name: st-agent-net
    driver: overlay
    attachable: true

Then you run:

docker stack deploy -c docker-compose.yml <name>

Read more about why Sematext Agent needs access to host files and directories.