How to Update TCP Keep-alive Parameters in VMs in Tanzu Application service for VMs

Products

• VMware Tanzu Application Service for VMs

Issue/Introduction

 

 

 

Environment

Resolution

In TAS, there is a feature called "add-ons" using bosh. This feature enables operators to run software is not part of the BOSH release - typically third-party monitoring agents, antivirus, security software, operating system kernel parameters etc.

To change TCP keepalive parameters in a kernel configuration, see detailed instructions below:

• Upload the os-conf-release:

The tar bundle of the release is provided here:

bosh upload release https://bosh.io/d/github.com/cloudfoundry/os-conf-release

• Create a runtime.yml manifest file and copy contents of https://github.com/cloudfoundry/os-conf-release/blob/master/manifests/tcp_keepalive.yml

• Update version in the release section of the manifest file to match the os-conf-release version (from bosh releases output, note the os-conf-release version)

• Add the TCP keep-alive properties in the yml file.

Sample file:

releases:
- name: os-conf
  version: 6

addons:
- name: networking
  jobs:
  - name: tcp_keepalive
    release: os-conf
  properties:
    tcp_keepalive:
      time: 121
      interval: 31
      probes: 9

• Update the runtime config on the director:

bosh update runtime-config ./runtime.yml

• Run bosh runtime-config to confirm

• Click "Apply Changes" in the Ops Manager.

• To verify the changes, ssh to the VM and run the following command:

  sysctl -a | grep tcp_keepalive
  

 

Note: The above procedure will update the kernel parameters across all of the VMs in the TAS cluster. There is no provision to update and persist the kernel settings on a per VM basis.