我正在处理一个项目，我的服务器需要交换空间以避免一些Python长时间运行的进程耗尽内存。我意识到我的Ubuntu Vagrant虚拟机和AWS Ubuntu实例都没有设置交换空间。
在https://github.com/ansible/ansible/issues/5241中讨论了可能的内置解决方案，但从未实现，因此我想这应该是一个相当常见的任务要实现自动化。
您将如何使用Ansible以可重复方式设置基于文件的交换空间？Ansible提供哪些模块或变量来帮助此设置（例如ansible_swaptotal_mb变量）？
这是我的目前解决方案：
- name: Create swap file
command: dd if=/dev/zero of={{ swap_file_path }} bs=1024 count={{ swap_file_size_mb }}k
creates="{{ swap_file_path }}"
tags:
- swap.file.create
- name: Change swap file permissions
file: path="{{ swap_file_path }}"
owner=root
group=root
mode=0600
tags:
- swap.file.permissions
- name: "Check swap file type"
command: file {{ swap_file_path }}
register: swapfile
tags:
- swap.file.mkswap
- name: Make swap file
command: "sudo mkswap {{ swap_file_path }}"
when: swapfile.stdout.find('swap file') == -1
tags:
- swap.file.mkswap
- name: Write swap entry in fstab
mount: name=none
src={{ swap_file_path }}
fstype=swap
opts=sw
passno=0
dump=0
state=present
tags:
- swap.fstab
- name: Mount swap
command: "swapon {{ swap_file_path }}"
when: ansible_swaptotal_mb < 1
tags:
- swap.file.swapon
creates="{{ swap_file_path }}"属性将处理这个问题，dd命令不会运行。我仍在生产环境中使用此功能，并且当前任务条件（when/creates）似乎正在发挥作用，即使这是幂等性的......你能详细说明一下可能会将文件清零的情况吗？ 请注意，我将原文中“idempotent”翻译为了“幂等性”。 - gonzk 导致的。将其删除后，它就像魔术般地运作了。这是在使用Centos 7.5系统时发生的。 - Richard Balebs和末尾的k，swap_file_size_kb实际上是以兆字节为单位而不是千字节。 - James D我尝试了上面的答案，但是总是返回"Check swap file type"已经被更改，因此不符合幂等性。当编写Ansible任务时，这是一个最佳实践。
下面的角色已在Ubuntu 14.04 Trusty上进行了测试，并且不需要启用gather_facts。
- name: Set swap_file variable
set_fact:
swap_file: "{{swap_file_path}}"
tags:
- swap.set.file.path
- name: Check if swap file exists
stat:
path: "{{swap_file}}"
register: swap_file_check
tags:
- swap.file.check
- name: Create swap file
command: fallocate -l {{swap_file_size}} {{swap_file}}
when: not swap_file_check.stat.exists
tags:
- swap.file.create
- name: Change swap file permissions
file: path="{{swap_file}}"
owner=root
group=root
mode=0600
tags:
- swap.file.permissions
- name: Format swap file
sudo: yes
command: "mkswap {{swap_file}}"
when: not swap_file_check.stat.exists
tags:
- swap.file.mkswap
- name: Write swap entry in fstab
mount: name=none
src={{swap_file}}
fstype=swap
opts=sw
passno=0
dump=0
state=present
tags:
- swap.fstab
- name: Turn on swap
sudo: yes
command: swapon -a
when: not swap_file_check.stat.exists
tags:
- swap.turn.on
- name: Set swappiness
sudo: yes
sysctl:
name: vm.swappiness
value: "{{swappiness}}"
tags:
- swap.set.swappiness
从Ansible 2.9版本开始，sudo声明应该改为become:
- name: Set swap_file variable
set_fact:
swap_file: "{{swap_file_path}}"
tags:
- swap.set.file.path
- name: Check if swap file exists
stat:
path: "{{swap_file}}"
register: swap_file_check
tags:
- swap.file.check
- name: Create swap file
command: fallocate -l {{swap_file_size}} {{swap_file}}
when: not swap_file_check.stat.exists
tags:
- swap.file.create
- name: Change swap file permissions
file: path="{{swap_file}}"
owner=root
group=root
mode=0600
tags:
- swap.file.permissions
- name: Format swap file
become: yes
command: "mkswap {{swap_file}}"
when: not swap_file_check.stat.exists
tags:
- swap.file.mkswap
- name: Write swap entry in fstab
mount: name=none
src={{swap_file}}
fstype=swap
opts=sw
passno=0
dump=0
state=present
tags:
- swap.fstab
- name: Turn on swap
become: yes
command: swapon -a
when: not swap_file_check.stat.exists
tags:
- swap.turn.on
- name: Set swappiness
become: yes
sysctl:
name: vm.swappiness
value: "{{swappiness}}"
tags:
- swap.set.swappiness
所需变量：
swap_file_path: /swapfile
# Use any of the following suffixes
# c=1
# w=2
# b=512
# kB=1000
# K=1024
# MB=1000*1000
# M=1024*1024
# xM=M
# GB=1000*1000*1000
# G=1024*1024*1024
swap_file_size: 4G
swappiness: 1
我基于伟大的Ashley的答案（请点赞！）并添加了以下额外功能：
...加上这些技术改进：
ok和skipping，否则使用一些changed），dd而不是fallocate以与XFS文件系统兼容（有关更多信息，请参见此答案），限制：
swap_file_path时，更改现有交换文件才能正常工作。在Centos 7.7上使用Ansible 2.9和Rocky 8上测试过与Ansible 4.8.0。
需要使用特权升级，因为许多命令需要以root身份运行。 （最简单的方法是将--become添加到ansible-playbook参数或在ansible.cfg中设置适当的值）。
参数：
swap_configure: true # or false
swap_enable: true # or false
swap_file_path: /swapfile
swap_file_size_mb: 4096
swappiness: 1
代码：
- name: Configure swap
when: swap_configure | bool
block:
- name: Check if swap file exists
stat:
path: "{{swap_file_path}}"
get_checksum: false
get_md5: false
register: swap_file_check
changed_when: false
- name: Set variable for existing swap file size
set_fact:
swap_file_existing_size_mb: "{{ (swap_file_check.stat.size / 1024 / 1024) | int }}"
when: swap_file_check.stat.exists
- name: Check if swap is on
shell: swapon --show | grep {{swap_file_path}}
register: swap_is_enabled
changed_when: false
failed_when: false
- name: Disable swap
command: swapoff {{swap_file_path}}
register: swap_disabled
when: >
swap_file_check.stat.exists
and 'rc' in swap_is_enabled and swap_is_enabled.rc == 0
and (not swap_enable or (swap_enable and swap_file_existing_size_mb != swap_file_size_mb))
- name: Delete the swap file
file:
path: "{{swap_file_path}}"
state: absent
when: not swap_enable
- name: Remove swap entry from fstab
mount:
name: none
src: "{{swap_file_path}}"
fstype: swap
opts: sw
passno: '0'
dump: '0'
state: present
when: not swap_enable
- name: Configure swap
when: swap_enable | bool
block:
- name: Create or change the size of swap file
command: dd if=/dev/zero of={{swap_file_path}} count={{swap_file_size_mb}} bs=1MiB
register: swap_file_created
when: >
not swap_file_check.stat.exists
or swap_file_existing_size_mb != swap_file_size_mb
- name: Change swap file permissions
file:
path: "{{swap_file_path}}"
mode: 0600
- name: Check if swap is formatted
shell: file {{swap_file_path}} | grep 'swap file'
register: swap_file_is_formatted
changed_when: false
failed_when: false
- name: Format swap file if it's not formatted
command: mkswap {{swap_file_path}}
when: >
('rc' in swap_file_is_formatted and swap_file_is_formatted.rc > 0)
or swap_file_created.changed
- name: Add swap entry to fstab
mount:
name: none
src: "{{swap_file_path}}"
fstype: swap
opts: sw
passno: '0'
dump: '0'
state: present
- name: Turn on swap
shell: swapon -a
# if swap was disabled from the start
# or has been disabled to change its params
when: >
('rc' in swap_is_enabled and swap_is_enabled.rc != 0)
or swap_disabled.changed
- name: Configure swappiness
sysctl:
name: vm.swappiness
value: "{{ swappiness|string }}"
state: present
swap_emabled.rc != 0或swap_disabled.changed。 - lefterisnikswap_file_size_mb: "{{ ansible_memory_mb['real']['total'] * 2 }}"
这是我使用的ansible-swap playbook，用于在新服务器上安装4GB（或者我为group_vars中的dd_bs_size_mb* swap_count配置的任何值）交换空间：
https://github.com/tribou/ansible-swap
我还在我的~/.bash_profile中添加了一个函数来帮助完成这个任务：
# Path to where you clone the repo
ANSIBLE_SWAP_PLAYBOOK=$HOME/dev/ansible-swap
install-swap ()
{
usage='Usage: install-swap HOST';
if [ $# -ne 1 ]; then
echo "$usage";
return 1;
fi;
ansible-playbook $ANSIBLE_SWAP_PLAYBOOK/ansible-swap/site.yml --extra-vars "target=$1"
}
请确保首先将您的HOST添加到Ansible清单中。
然后只需执行install-swap HOST即可。
dd而不是fallocate（参考https://askubuntu.com/a/1017312）。我推荐使用general.community.filesize而不是内置的command，因为它包含适当的检查模式+使用dd，并以紧凑形式处理文件权限。swap_file_size_gb: "{{ ((ansible_memory_mb.real.total / 1000) ** 0.5) | round | int }}"
---
- name: add-swap-file | Check whether SWAP file exist
ansible.builtin.command:
cmd: swapon -s
register: swap_exist
no_log: true
changed_when: false
check_mode: false
- name: add-swap-file | Debug show server differences
ansible.builtin.debug:
msg: "Current swap file:\n{{ swap_exist.stdout }}\nRecommended swap file size: {{ swap_file_size_gb }}G"
verbosity: 1
- name: add-swap-file | Create and configure swap file
when: swap_exist.stdout | length == 0
block:
- name: add-swap-file | Create swap file
community.general.filesize:
path: "{{ swap_file_path }}"
size: "{{ swap_file_size_gb }}G"
blocksize: 1024
mode: "600"
owner: root
group: root
- name: add-swap-file | Check swap file type
ansible.builtin.command:
cmd: "file {{ swap_file_path }}"
register: swapfile
check_mode: false
changed_when: false
- name: add-swap-file | Make swap file
ansible.builtin.command:
cmd: "mkswap {{ swap_file_path }}"
when: swapfile.stdout.find('swap file') == -1
changed_when: true
- name: add-swap-file | Write swap entry in fstab
ansible.posix.mount:
name: none
src: "{{ swap_file_path }}"
fstype: swap
opts: sw
passno: 0
dump: 0
state: present
- name: add-swap-file | Mount swap
ansible.builtin.command:
cmd: "swapon {{ swap_file_path }}"
when: ansible_swaptotal_mb < 1
changed_when: true
.