Batch SizeΒΆ
The batch size option allows commands to be executed while maintaining that only so many hosts are executing the command at one time. This option can take a percentage or a finite number:
salt \* -b 10 test.ping
salt -G 'os:RedHat' --batch-size 25% apache.signal restart
This will only run test.ping on 10 of the targeted minions at a time and then restart apache on 25% of the minions matching os:RedHat at a time and work through them all until the task is complete. This makes jobs like rolling web server restarts behind a load balancer or doing maintenance on BSD firewalls using carp much easier with salt.
The batch system maintains a window of running minions, so, if there are a total of 150 minions targeted and the batch size is 10, then the command is sent to 10 minions, when one minion returns then the command is sent to one additional minion, so that the job is constantly running on 10 minions.
