Ansible Performance | James Tanner

Imported from the legacy wiki archive. The date above is inferred from the strongest available evidence and may represent a known range rather than the exact publication day.

areas of performance

Every layer of the stack as described in https://tannerjc.net/wiki/index.php?title=Ansible_Hangs_Filament#Tools_By_Layer is potentially a source of performance issues.

strategies

getting started

many tasks

many hosts

many groups

many vars

metrics

duration

[https://en.wikipedia.org/wiki/Duration Duration] is a measurement of time. There are multiple facets of “duration” when observing Ansible.

total duration of a playbook
total duration of a task
total duration of a host within a task
total duration of an ssh call for a host within a task
total duration of wating for a sudo password prompt
total duration of executing python on the remote host
total duration of processing the results for a host/worker

cpu utilization

Aka [https://en.wikipedia.org/wiki/CPU_time CPU time]. Many tools exist to measure cpu time / utilization and it’s important to understand the various metrics each provides.

https://access.redhat.com/solutions/1160343

An important metric for basic ansible cpu utilization is the “b” (aka “blocked) column from vmstat.

https://linux.die.net/man/8/vmstat http://www.dba-oracle.com/t_linux_oracle_vmstat.htm https://access.redhat.com/solutions/792683

Multiple factors could cause the number of blocked processes to accumulate.

not enough cpu cores
setting ansible’s fork count too high
not enough memory
too many hosts returning too much data for the controller to handle
not enough disk IOPs

=== memory utilization ===

disk utilization

network utilization

tools

https://docs.ansible.com/ansible/devel/plugins/callback/cgroup_memory_recap.html https://github.com/jctanner/ansible-tools/blob/master/ansible_debug_logparser

https://github.com/ansible/qa-scale-lab https://github.com/jctanner/ansible-tools/tree/master/vagrant/ansible_test_inventory

labs

https://github.com/jctanner/ansible-tools/tree/master/playbooks/slowhost

training

https://www.redhat.com/en/services/training/rh442-red-hat-enterprise-performance-tuning https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/performance_tuning_guide/chap-red_hat_enterprise_linux-performance_tuning_guide-performance_monitoring_tools

additional reading

https://gist.github.com/sivel/ef405e70f699ce29c49cfdf6104a0492