e0ba55a85d
One way to improve the performance of Ansible is through fact caching. Rather than gather facts in every play, we can configure Ansible to cache them in a persistent store. An example Ansible configuration for doing this is as follows: [defaults] gathering = smart fact_caching = jsonfile fact_caching_connection = ./facts fact_caching_timeout = 86400 This does not affect Kolla Ansible however, since we use the setup module which unconditionally gathers facts regardless of the state of the cache. This gets worse with large inventories limited to a small batch of hosts via --limit or serial, since the limited hosts must gather facts for all others. One way to detect whether facts exist for a host is via the 'module_setup' variable, which exists only when facts exist. This change uses the 'module_setup' fact to determine whether facts need to be gathered for hosts outside of the batch. For hosts in the batch, we switch from using the setup module to gather_facts on the play, which can use the 'smart' gathering logic. Change-Id: I04841fb62b2e1d9e97ce4b75ce3a7349b9c74036 Partially-Implements: blueprint performance-improvements
41 lines
1.6 KiB
YAML
41 lines
1.6 KiB
YAML
---
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# NOTE(awiddersheim): Gather facts for all hosts as a
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# first step since several plays below require them when
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# building their configurations.
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- name: Gather facts for all hosts
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hosts: all
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serial: '{{ kolla_serial|default("0") }}'
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gather_facts: true
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tasks:
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- name: Group hosts to determine when using --limit
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group_by:
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key: "all_using_limit_{{ (ansible_play_batch | length) != (groups['all'] | length) }}"
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tags: always
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# NOTE(pbourke): This case covers deploying subsets of hosts using --limit. The
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# limit arg will cause the first play to gather facts only about that node,
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# meaning facts such as IP addresses for rabbitmq nodes etc. will be undefined
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# in the case of adding a single compute node.
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# NOTE(mgoddard): Divide all hosts to be queried between the hosts selected via
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# the limit.
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- name: Gather facts for all hosts (if using --limit)
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hosts: all_using_limit_True
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serial: '{{ kolla_serial|default("0") }}'
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gather_facts: false
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vars:
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batch_index: "{{ ansible_play_batch.index(inventory_hostname) }}"
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batch_size: "{{ ansible_play_batch | length }}"
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# Use a python list slice to divide the group up.
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# Syntax: [<start index>:<end index>:<step size>]
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delegate_hosts: "{{ groups['all'][batch_index | int::batch_size | int] }}"
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tasks:
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- name: Gather facts
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setup:
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delegate_facts: True
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delegate_to: "{{ item }}"
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with_items: "{{ delegate_hosts }}"
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# We gathered facts for all hosts in the batch during the first play.
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when:
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- not hostvars[item].module_setup | default(false)
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tags: always
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