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历经千辛万苦，终于有了自己的openstack开发环境，查看《allinone—openstack development environment》，就想新交了女朋友一样，是不是想要更进一步的了解她呢？

all到底包含哪些

怀着激动的心情，就让我们一步一步的走进allinone的内心世界吧，在命令行敲入：

systemctl list-unit-files | grep openstack

systemctl的使用可以参考我的另外一篇博客《systemctl介绍》，上面的命令可以列出当前系统中所有已安装的服务。allinone环境会得到如下的输出：

# systemctl list-unit-files | grep openstack
openstack-ceilometer-alarm-evaluator.service  enabled 
openstack-ceilometer-alarm-notifier.service   enabled 
openstack-ceilometer-api.service              enabled 
openstack-ceilometer-central.service          enabled 
openstack-ceilometer-collector.service        enabled 
openstack-ceilometer-compute.service          enabled 
openstack-ceilometer-notification.service     enabled 
openstack-ceilometer-polling.service          disabled
openstack-cinder-api.service                  enabled 
openstack-cinder-backup.service               enabled 
openstack-cinder-scheduler.service            enabled 
openstack-cinder-volume.service               enabled 
openstack-glance-api.service                  enabled 
openstack-glance-registry.service             enabled 
openstack-glance-scrubber.service             disabled
openstack-keystone.service                    disabled
openstack-losetup.service                     enabled 
openstack-nova-api.service                    enabled 
openstack-nova-cert.service                   enabled 
openstack-nova-compute.service                enabled 
openstack-nova-conductor.service              enabled 
openstack-nova-console.service                disabled
openstack-nova-consoleauth.service            enabled 
openstack-nova-metadata-api.service           disabled
openstack-nova-novncproxy.service             enabled 
openstack-nova-scheduler.service              enabled 
openstack-nova-xvpvncproxy.service            disabled
openstack-swift-account-auditor.service       enabled 
openstack-swift-account-auditor@.service      disabled
openstack-swift-account-reaper.service        enabled 
openstack-swift-account-reaper@.service       disabled
openstack-swift-account-replicator.service    enabled 
openstack-swift-account-replicator@.service   disabled
openstack-swift-account.service               enabled 
openstack-swift-account@.service              disabled
openstack-swift-container-auditor.service     enabled 
openstack-swift-container-auditor@.service    disabled
openstack-swift-container-reconciler.service  disabled
openstack-swift-container-replicator.service  enabled 
openstack-swift-container-replicator@.service disabled
openstack-swift-container-updater.service     enabled 
openstack-swift-container-updater@.service    disabled
openstack-swift-container.service             enabled 
openstack-swift-container@.service            disabled
openstack-swift-object-auditor.service        enabled 
openstack-swift-object-auditor@.service       disabled
openstack-swift-object-expirer.service        enabled 
openstack-swift-object-replicator.service     enabled 
openstack-swift-object-replicator@.service    disabled
openstack-swift-object-updater.service        enabled 
openstack-swift-object-updater@.service       disabled
openstack-swift-object.service                enabled 
openstack-swift-object@.service               disabled
openstack-swift-proxy.service                 enabled 
# 

细心的读者应该会发现，图中总共包含了ceilometer、cinder、glance、keystone、nova、swift六个组件的单元，另外的neutron去哪儿了？让我们再找找，输入如下的命令：

systemctl list-unit-files | grep neutron

原来是这小子搞特殊化哦

# systemctl list-unit-files | grep neutron
neutron-dhcp-agent.service                    enabled 
neutron-l3-agent.service                      enabled 
neutron-metadata-agent.service                enabled 
neutron-netns-cleanup.service                 disabled
neutron-openvswitch-agent.service             enabled 
neutron-ovs-cleanup.service                   enabled 
neutron-server.service                        enabled 
#

所有可用的单元文件存放在 /usr/lib/systemd/system/ 和 /etc/systemd/system/ 目录（后者优先级更高），我们再来看看openstack各服务的文件，用户安装的服务一般放在/usr/lib/systemd/system/目录下，命令如下：

ls -lh /usr/lib/systemd/system/ | grep openstack

得到的结果如下：

# ls -lh /usr/lib/systemd/system/ | grep openstack
-rw-r--r--. 1 root root 274 Dec 22 06:38 openstack-ceilometer-alarm-evaluator.service -rw-r--r--. 1 root root 274 Dec 22 06:38 openstack-ceilometer-alarm-notifier.service -rw-r--r--. 1 root root 237 Dec 22 06:38 openstack-ceilometer-api.service -rw-r--r--. 1 root root 276 Dec 22 06:38 openstack-ceilometer-central.service -rw-r--r--. 1 root root 256 Dec 22 06:38 openstack-ceilometer-collector.service -rw-r--r--. 1 root root 276 Dec 22 06:38 openstack-ceilometer-compute.service -rw-r--r--. 1 root root 274 Dec 22 06:38 openstack-ceilometer-notification.service -rw-r--r--. 1 root root 316 Dec 22 06:38 openstack-ceilometer-polling.service -rw-r--r--. 1 root root 307 Dec 22 23:27 openstack-cinder-api.service -rw-r--r--. 1 root root 316 Dec 22 23:27 openstack-cinder-backup.service -rw-r--r--. 1 root root 325 Dec 22 23:27 openstack-cinder-scheduler.service -rw-r--r--. 1 root root 316 Dec 22 23:27 openstack-cinder-volume.service -rw-r--r--. 1 root root 261 Feb 5 15:26 openstack-glance-api.service -rw-r--r--. 1 root root 271 Feb 5 15:26 openstack-glance-registry.service -rw-r--r--. 1 root root 267 Feb 5 15:26 openstack-glance-scrubber.service -rw-r--r--. 1 root root 242 Dec 22 02:52 openstack-keystone.service -rw-r--r--. 1 root root 571 Mar 21 17:55 openstack-losetup.service -rwxr-xr-x. 1 root root 230 Jan 25 19:28 openstack-nova-api.service -rwxr-xr-x. 1 root root 232 Jan 25 19:28 openstack-nova-cert.service -rwxr-xr-x. 1 root root 285 Jan 25 19:28 openstack-nova-compute.service -rwxr-xr-x. 1 root root 242 Jan 25 19:28 openstack-nova-conductor.service -rwxr-xr-x. 1 root root 251 Jan 25 19:28 openstack-nova-consoleauth.service -rwxr-xr-x. 1 root root 244 Jan 25 19:28 openstack-nova-console.service -rwxr-xr-x. 1 root root 248 Jan 25 19:28 openstack-nova-metadata-api.service -rwxr-xr-x. 1 root root 285 Jan 25 19:28 openstack-nova-novncproxy.service -rwxr-xr-x. 1 root root 242 Jan 25 19:28 openstack-nova-scheduler.service -rwxr-xr-x. 1 root root 197 Jan 25 19:28 openstack-nova-xvpvncproxy.service -rw-r--r--. 1 root root 286 Oct 1 05:29 openstack-swift-account-auditor.service -rw-r--r--. 1 root root 264 Oct 1 05:29 openstack-swift-account-auditor@.service -rw-r--r--. 1 root root 247 Oct 1 05:29 openstack-swift-account-reaper.service -rw-r--r--. 1 root root 262 Oct 1 05:29 openstack-swift-account-reaper@.service -rw-r--r--. 1 root root 322 Oct 1 05:29 openstack-swift-account-replicator.service -rw-r--r--. 1 root root 270 Oct 1 05:29 openstack-swift-account-replicator@.service -rw-r--r--. 1 root root 282 Oct 1 05:29 openstack-swift-account.service -rw-r--r--. 1 root root 297 Oct 1 05:29 openstack-swift-account@.service -rw-r--r--. 1 root root 255 Oct 1 05:29 openstack-swift-container-auditor.service -rw-r--r--. 1 root root 270 Oct 1 05:29 openstack-swift-container-auditor@.service -rw-r--r--. 1 root root 265 Oct 1 05:29 openstack-swift-container-reconciler.service -rw-r--r--. 1 root root 328 Oct 1 05:29 openstack-swift-container-replicator.service -rw-r--r--. 1 root root 276 Oct 1 05:29 openstack-swift-container-replicator@.service -rw-r--r--. 1 root root 288 Oct 1 05:29 openstack-swift-container.service -rw-r--r--. 1 root root 303 Oct 1 05:29 openstack-swift-container@.service -rw-r--r--. 1 root root 255 Oct 1 05:29 openstack-swift-container-updater.service -rw-r--r--. 1 root root 270 Oct 1 05:29 openstack-swift-container-updater@.service -rw-r--r--. 1 root root 283 Oct 1 05:29 openstack-swift-object-auditor.service -rw-r--r--. 1 root root 261 Oct 1 05:29 openstack-swift-object-auditor@.service -rw-r--r--. 1 root root 247 Oct 1 05:29 openstack-swift-object-expirer.service -rw-r--r--. 1 root root 319 Oct 1 05:29 openstack-swift-object-replicator.service -rw-r--r--. 1 root root 267 Oct 1 05:29 openstack-swift-object-replicator@.service -rw-r--r--. 1 root root 279 Oct 1 05:29 openstack-swift-object.service -rw-r--r--. 1 root root 294 Oct 1 05:29 openstack-swift-object@.service -rw-r--r--. 1 root root 246 Oct 1 05:29 openstack-swift-object-updater.service -rw-r--r--. 1 root root 261 Oct 1 05:29 openstack-swift-object-updater@.service -rw-r--r--. 1 root root 276 Oct 1 05:29 openstack-swift-proxy.service #

查看neutron服务文件，ls -lh /usr/lib/systemd/system/ | grep neutron，得到的结果：

# ls -lh /usr/lib/systemd/system/ | grep neutron
-rw-r--r--. 1 root root  497 Dec 22 03:25 neutron-dhcp-agent.service
-rw-r--r--. 1 root root  493 Dec 22 03:25 neutron-l3-agent.service
-rw-r--r--. 1 root root  517 Dec 22 03:25 neutron-metadata-agent.service
-rw-r--r--. 1 root root  987 Dec 22 03:25 neutron-netns-cleanup.service
-rw-r--r--. 1 root root  584 Dec 22 03:25 neutron-openvswitch-agent.service
-rw-r--r--. 1 root root 1011 Dec 22 03:25 neutron-ovs-cleanup.service
-rw-r--r--. 1 root root  532 Dec 22 03:25 neutron-server.service
# 

服务到启动脚本

找到了服务文件，就好比找到了女朋友心灵的某个入口，会打开一片新的天地，让你见识一个全新的世界，我们就来撕开这个领口，看一看这个全新的世界，以openstack-ceilometer-api.service为例：

# cat /usr/lib/systemd/system/openstack-ceilometer-api.service 
[Unit]
Description=OpenStack ceilometer API service
After=syslog.target network.target

[Service]
Type=simple
User=ceilometer
ExecStart=/usr/bin/ceilometer-api --logfile /var/log/ceilometer/api.log

[Install]
WantedBy=multi-user.target

# 

重点看一下ExecStart=/usr/bin/ceilometer-api --logfile /var/log/ceilometer/api.log发现跟

# ps -ef | grep ceilometer-api
ceilome+  1168     1  3 Mar24 ?        00:14:48 /usr/bin/python2 /usr/bin/ceilometer-api --logfile /var/log/ceilometer/api.log

的输出结果一致，这就是ceilometer-api的启动命令，启动脚本为/usr/bin/ceilometer-api

启动脚本到代码

如果你是一个好奇心很强的程序员，想要刨根究底，那么这就是ceilometer-api的入口了，快去看看里面都写了些什么吧，我的代码是Liberty版本的5.0.2Tag，跟master分支上的代码有较大的差别，后需要将按照master分支上的代码进行整理，我的ceilometer-api启动脚本内容为：

#!/usr/bin/python2
# PBR Generated from u'console_scripts'

import sys

from ceilometer.cmd.api import main


if __name__ == "__main__":
    sys.exit(main())

你已经从操作系统上正确的找到一个openstack组件服务的入口了，接下来就可以对接上你熟悉的代码了，加油！