Updating Zato environments

Each major release receives periodic updates to functionality, including security and stability fixes. Each such update is always backwards-compatible within the same major release.

To install updates, run the commands below in each VM that hosts any Zato component - servers, scheduler, load-balancer or dashboard:

• Obtain and install the latest updates:

  sudo su - zato
  cd /opt/zato/current
  git pull
  ./update.sh
  

• Afterwards, all Zato components need to be stopped and started again. To increase high-availability, stop and start the components in the order as below, which will ensure that the window of time without any server available is as small as possible:

  • Stop/start web-admin

  • Stop/start each of servers, one by one, waiting for each to boot up before proceeding to the next one

  • Stop/start the load-balancer

  • Stop/start the scheduler

• The commands to stop and start web-admin, load-balancer and scheduler are zato stop and zato start

• The command to stop servers is also zato stop but, additionally and unlike the dashboard or load-balancer, Zato servers need to be started with the --sync-internal flag, as below:

  zato start /path/to/server --sync-internal
  

• Flag --sync-internal triggers re-synchronization of internal caches, which lets servers start faster. Consequently, this flag should be used only after code updates and its continuous usage in other circumstances is detrimental to performance, use it only after following the instructions in this chapter, otherwise do not use the --sync-internal flag.