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Use blockinfile for tripleo-ssh-known-hosts

lineinfile combined with with_items was very inefficient for this task.
Given that each node's hostkey is added to every other host, it resulted
in O(n²) performance.

Additional networks per node also worsened the problem. For example, in
a 100 node deployment, with 4 networks per node, this task would need to
be executed 40,000 times (100 * 100 * 4).

Switching to use blockinfile brings the performance back to O(n), and
also removes any dependency on the number of networks per node. This
change also backports the task layout which improves general performance
and functionality of the role.

Change-Id: Id51d27f53abf3421c29a11065377e9303ad68d79
(cherry picked from commit 4157d7a5df)
Signed-off-by: Kevin Carter <kecarter@redhat.com>
changes/82/681082/2
Kevin Carter 2 years ago
committed by Kevin Carter (cloudnull)
parent
commit
ddf5afa2c3
1 changed files with 40 additions and 10 deletions
  1. +40
    -10
      roles/tripleo-ssh-known-hosts/tasks/main.yml

+ 40
- 10
roles/tripleo-ssh-known-hosts/tasks/main.yml View File

@ -9,21 +9,51 @@
tempfile:
state: file
register: ssh_known_hosts_tmp
- name: Check for ssh_known_hosts file
stat:
path: /etc/ssh/ssh_known_hosts
register: _ssh_known_hosts
- name: Create a temporary copy of ssh_known_hosts
shell: |
if [[ -e /etc/ssh/ssh_known_hosts ]]; then
cat /etc/ssh/ssh_known_hosts > '{{ ssh_known_hosts_tmp.path }}'
fi
slurp:
src: "/etc/ssh/ssh_known_hosts"
register: existing_ssh_known_hosts
when:
- _ssh_known_hosts.stat.exists | bool
- name: Write temporary file
copy:
content: "{{ existing_ssh_known_hosts['content'] | b64decode }}"
dest: "{{ ssh_known_hosts_tmp.path }}"
when:
- _ssh_known_hosts.stat.exists | bool
- name: Set ssh_known_hosts fact
run_once: true
set_fact:
ssh_known_hosts_lines: |-
{%- for item in groups['overcloud'] | intersect(play_hosts) %}
{{ ssh_known_hosts[hostvars[item]['ansible_hostname'] | lower] ~ ' ssh-rsa ' ~ hostvars[item]['ansible_ssh_host_key_rsa_public'] }}
{% endfor %}
- name: Add host keys to temporary ssh_known_hosts
lineinfile:
blockinfile:
path: "{{ ssh_known_hosts_tmp.path }}"
line: "{{ ssh_known_hosts[hostvars[item]['ansible_hostname'] | lower] + ' ssh-rsa ' + hostvars[item]['ansible_ssh_host_key_rsa_public'] }}"
create: yes
with_items: "{{ groups['overcloud']|intersect(play_hosts) }}"
block: "{{ ssh_known_hosts_lines }}"
create: true
# Workaround https://bugs.launchpad.net/tripleo/+bug/1810932
# Ansible modules perform a replace instead of in-place modification.
# This breaks propagation of changes to containers that bind mount ssh_known_hosts
- name: In-place update of /etc/ssh_known_hosts
shell: |
shell: |-
cat '{{ ssh_known_hosts_tmp.path }}' > /etc/ssh/ssh_known_hosts
rm -f '{{ ssh_known_hosts_tmp.path }}'
- name: Remove temp file
file:
path: "{{ ssh_known_hosts_tmp.path }}"
state: absent
tags:
- tripleo_ssh_known_hosts

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