How to add additional agents to mesosphere dc/os cluster?

Question

We have Mesosphere DC/OS version 1.7 running on 6 vmware vm's with rhel7 and we would now like to add more agents. We were able to increase from our initial 2 agents(vms) to 6 agents(vms) by running dcos_generate_confg.sh --uninstall from the boot node. We then added the new ip addresses to the agent list in genconf/config.yaml and ran --genconf, --preflight, --deploy, --postflight. This worked however the --uninstall blew away our existing public agent, which we had to go back in and re-install.

Is there another way to add agents without running the --uninstall? Very nervous about what that's doing under the hood. Thank you!

Answer 1

For my part, I also had trouble understanding how to add a node to a cluster, then I found this link that allowed me to do this:

The Mesosphere guide to getting started with DC/OS: Part 2

Go to the "Adding an internet-facing HAproxy load balancer" chapter.

To summarize what I did and which worked:

• BootStrap Node:

  sudo vi ~/genconf/config.yaml ## add node slave IP
  
  sudo ./dcos_generate_config.sh --install-prereqs
  
  sudo ./dcos_generate_config.sh --preflight
  

You can ignore errors from the existing agents and masters—DC/OS is just telling you it’s already installed, and you probably don’t want to clobber that installation in-place.

sudo scp -r -i genconf/ssh_key genconf/serve $NEW_NODE_IP:~ ## Copy to the node

• New node:

  sudo mkdir /opt/dcos_install_tmp
  
  sudo cp -r serve/* /opt/dcos_install_tmp/
  
  cd /opt/dcos_install_tmp/
  chmod +x dcos_install.sh
  
  Agent Private
  
       sudo ./dcos_install.sh slave
  
  Agent Public
  
       sudo ./dcos_install.sh slave_public
  

• BootStrap node:

  sudo ./dcos_generate_config.sh --postflight
  

I hope that this can help you!