Packstack

简介

Packstack主要是由Redhat推出的用于概念验证(PoC)环境快速部署的工具。Packstack是一个命令行工具,它使用Python封装了Puppet模块,通过SSH在服务器上部署OpenStack。

Packstack支持三种运行模式:

  • 快速运行

  • 交互式运行

  • 非交互式运行

Packstack支持两种部署架构:

  • All-in-One,即所有的服务部署到一台服务器上

  • Multi-Node,即控制节点和计算机分离

因为Redhat官方有详细的使用文档,因此本文将简要介绍Packstack的快速运行以及交互式运行方式来部署All-in-One的Openstack。

部署前准备

在开始部署前,我们需要准备一台虚拟机,它的规格如下:

名称

要求

处理器

推荐2核以上

内存

推荐4G以上

磁盘

推荐20G以上

网卡

至少一块1G网卡

操作系统

CentOS7.2

在完成虚拟机的配置和启动后,在终端下输入以下指令:

$ sudo yum install -y https://www.rdoproject.org/repos/rdo-release.rpm
$ sudo yum update -y
$ sudo yum install -y openstack-packstack

快速运行

快速运行模式,表示用户可以对参数不做任何配置即可开始部署,用户只需要决定是单节点还是多节点的部署方式。

单节点

在packstack命令后,使用--allinonec参数在本机上部署所有服务。

$ packstack --allinone

多节点

使用--install-hosts参数来运行packstack,该参数值是由一个逗号隔开的IP地址列表。

$ packstack --install-hosts=CONTROLLER_ADDRESS,NODE_ADDRESSES

Packstack在部署完成后在终端上会输出以下信息:

**** Installation completed successfully ******

交互式运行

1.如果希望以交互式的方式来配置集群的部署,可以在终端下输入:

# packstack

2.packstack会提示你输入一个用于保存公共密钥的路径,输入Enter,则 会使用默认的~/.ssh/id_rsa.pub

Enter the path to your ssh Public key to install on servers:

3.packstack提示输入一个默认密码,该密码将作为admin user密码, 不输入则随机生成:

Enter a default password to be used. Leave blank for a randomly generated one. :

4.输入每个wsgi服务的进程数,默认等于cpu的核数:

Enter the amount of service workers/threads to use for each service. Leave blank to use the default. [%{::processorcount}] :

5.确认是否要安装MariaDB数据库,默认为y:

Should Packstack install MariaDB [y|n] [y] :

6.确认是否安装Openstack组件,可以根据需要定制服务:

Should Packstack install OpenStack Image Service (Glance) [y|n] [y] :
Should Packstack install OpenStack Block Storage (Cinder) [y|n] [y] :
Should Packstack install OpenStack Shared File System (Manila) [y|n] [n] :
Should Packstack install OpenStack Compute (Nova) [y|n] [y] :
Should Packstack install OpenStack Networking (Neutron) [y|n] [y] :
Should Packstack install OpenStack Dashboard (Horizon) [y|n] [y] :
Should Packstack install OpenStack Object Storage (Swift) [y|n] [y] :
Should Packstack install OpenStack Metering (Ceilometer) [y|n] [y] :
Should Packstack install OpenStack Telemetry Alarming (Aodh) [y|n] [y] :
Should Packstack install OpenStack Resource Metering (Gnocchi) [y|n] [y] :
Should Packstack install OpenStack Clustering (Sahara). If yes it'll also install Heat. [y|n] [n] :
Should Packstack install OpenStack Orchestration (Heat) [y|n] [n] :
Should Packstack install OpenStack Database (Trove) [y|n] [n] :
Should Packstack install OpenStack Bare Metal (Ironic) [y|n] [n] :
Should Packstack install OpenStack client tools [y|n] [y] :

7.Packstack为所有服务配置NTP服务来校准系统时间,NTP的设置只对多节点有意义:

Enter a comma separated list of NTP server(s). Leave plain if Packstack should not install ntpd on instances:

8.是否安装Nagios监控服务:

Should Packstack install Nagios to monitor OpenStack hosts [y|n] [y] :

9.哪些服务器在本次安装中被排除在外:

Enter a comma separated list of server(s) to be excluded. Leave plain if you don't need to exclude any server.:

10.是否启用调试模式:

Do you want to run OpenStack services in debug mode [y|n] [n] :

11.指定控制器的地址:

Enter the controller host [10.211.55.8] :

12.指定计算节点的地址:

Enter list of compute hosts [10.211.55.8] :

13.指定网络节点的地址:

Enter list of network hosts [10.211.55.8] :

14.是否使用VMWare vCenter作为hypervisor和datastore的后端:

Do you want to use VMware vCenter as hypervisor and datastore [y|n] [n] :

15.指定是否使用不支持的参数,推荐使用默认设置:

Enable this on your own risk. Do you want to use unsupported parameters [y|n] [n] :

16.网卡名称是否被自动识别为子网+CIDR的格式:

Should interface names be automatically recognized based on subnet CIDR [y|n] [n] :

17.是否为每个服务器订阅Extra Packstacks for Enterprise Linux(EPEL),建议使用默认设置:

To subscribe each server to EPEL enter "y" [y|n] [n] :

18.是否启用自定义的软件包仓库:

Enter a comma separated list of URLs to any additional yum repositories to install:

19.是否启用rdo test:

To enable rdo testing enter "y" [y|n] [n] :

20.是否启用Red Hat订阅,跳过即可:

To subscribe each server to Red Hat enter a username :
To subscribe each server with RHN Satellite enter RHN Satellite server URL:

21.ssl证书相关的操作:

Enter the filename of the SSL CAcertificate, if the CONFIG_SSL_CACERT_SELFSIGN is set to y the path will be CONFIG_SSL_CERT_DIR/certs/selfcert.crt [/etc/pki/tls/certs/selfcert.crt] :
Enter the filename of the SSL CAcertificate Key file, if the CONFIG_SSL_CACERT_SELFSIGN is set to y the path will be CONFIG_SSL_CERT_DIR/keys/selfkey.key [/etc/pki/tls/private/selfkey.key] :
Enter the path to use to store generated SSL certificates in [~/packstackca/] :
Should packstack use selfsigned CAcert. [y|n] [y] :
Enter the ssl certificates subject country. [--] :
Enter the ssl certificates subject state. [State] :
Enter the ssl certificate subject location. [City] :
Enter the ssl certificate subject organization. [openstack] :
Enter the ssl certificate subject organizational unit. [packstack] :
Enter the ssl certificaate subject common name. [centos-7.1.shared] :
Enter the ssl certificate subject admin email. [[email protected]] :

22.配置AMQP服务,默认会使用RabbitMQ作为backend,不启用身份验证和SSL:

Set the AMQP service backend [rabbitmq] [rabbitmq] :
Enter the host for the AMQP service [10.211.55.8] :
Enable SSL for the AMQP service? [y|n] [n] :
Enable Authentication for the AMQP service? [y|n] [n] :

23.配置MariaDB服务

Enter the IP address of the MariaDB server [10.211.55.8] :
Enter the password for the MariaDB admin user :
Confirm password :

24.配置Identity服务,包括设置数据库连接的密码,创建默认的admin,demo用户等基本操作:

Enter the password for the Keystone DB access :
Confirm password :
Enter y if cron job for removing soft deleted DB rows should be created [y|n] [y] :
Confirm password [y|n] [y] :
Region name [RegionOne] :
Enter the email address for the Keystone admin user [[email protected]] :
Enter the username for the Keystone admin user [admin] :
Enter the password for the Keystone admin user :
Confirm password :
Enter the password for the Keystone demo user :
Confirm password :
Enter the Keystone identity backend type. [sql|ldap] [sql] :

25.配置Image服务,包括设置数据库连接密码,glance用户密码,后端存储:

Enter the password for the Glance DB access :
Confirm password :
Enter the password for the Glance Keystone access :
Confirm password :
Glance storage backend [file|swift] [file] :

26.配置块存储服务,包括设置数据库连接密码,cinder用户和密码:

Enter the password for the Cinder DB access :
Confirm password :
Enter y if cron job for removing soft deleted DB rows should be created [y|n] [y] :
Confirm password [y|n] [y] :
Enter the password for the Cinder Keystone access :
Confirm password :
Enter the Cinder backend to be configured [lvm|gluster|nfs|vmdk|netapp|solidfire] [lvm] :
Should Cinder's volumes group be created (for proof-of-concept installation)? [y|n] [y] :
Enter Cinder's volumes group usable size [20G] :
Enter y if cron job for removing soft deleted DB rows should be created [y|n] [y] :
Confirm password [y|n] [y] :

27.配置计算服务,包括flavor,资源虚拟比,迁移,虚拟化软件等参数的设置:

Should Packstack manage default Nova flavors [y|n] [y] :
Enter the CPU overcommitment ratio. Set to 1.0 to disable CPU overcommitment [16.0] :
Enter the RAM overcommitment ratio. Set to 1.0 to disable RAM overcommitment [1.5] :
Enter protocol which will be used for instance migration [tcp|ssh] [tcp] :
Enter the compute manager for nova migration [nova.compute.manager.ComputeManager] :
Enter the path to a PEM encoded certificate to be used on the https server, leave blank if one should be generated, this certificate should not require a passphrase:
Enter the SSL keyfile corresponding to the certificate if one was entered:
Enter the PCI passthrough array of hash in JSON style for controller eg. [{'vendor_id':'1234', 'product_id':'5678', 'name':'default'}, {...}] :
Enter the PCI passthrough whitelist as array of hash in JSON style for controller eg. [{'vendor_id':'1234', 'product_id':'5678', 'name':'default'}, {...}]:
The nova hypervisor that should be used. Either qemu or kvm. [qemu|kvm] [%{::default_hypervisor}] :
Confirm password [qemu|kvm] [%{::default_hypervisor}] :

28.配置网络服务,包括从组件,接口,网络驱动等细节的设置:

Enter the password for Neutron Keystone access :
Confirm password :
Enter the password for Neutron DB access :
Confirm password :
Enter the ovs bridge the Neutron L3 agent will use for external traffic, or 'provider' if using provider networks. [br-ex] :
Enter Neutron metadata agent password :
Confirm password :
Should Packstack install Neutron LBaaS [y|n] [n] :
Should Packstack install Neutron L3 Metering agent [y|n] [y] :
Would you like to configure neutron FWaaS? [y|n] [n] :
Would you like to configure neutron VPNaaS? [y|n] [n] :
Enter a comma separated list of network type driver entrypoints [local|flat|vlan|gre|vxlan] [vxlan] :
Enter a comma separated ordered list of network_types to allocate as tenant networks [local|vlan|gre|vxlan] [vxlan] :
Enter a comma separated ordered list of networking mechanism driver entrypoints [logger|test|linuxbridge|openvswitch|hyperv|ncs|arista|cisco_nexus|mlnx|l2population|sriovnicswitch] [openvswitch] :
Enter a comma separated list of physical_network names with which flat networks can be created [*] :
Enter a comma separated list of physical_network names usable for VLAN:
Enter a comma separated list of <tun_min>:<tun_max> tuples enumerating ranges of GRE tunnel IDs that are available for tenant network allocation:
Enter a multicast group for VXLAN:
Enter a comma separated list of <vni_min>:<vni_max> tuples enumerating ranges of VXLAN VNI IDs that are available for tenant network allocation [10:100] :
Enter the name of the L2 agent to be used with Neutron [linuxbridge|openvswitch] [openvswitch] :
Enter a comma separated list of supported PCI vendor devices, defined by vendor_id:product_id according to the PCI ID Repository. [['15b3:1004', '8086:10ca']] :
Set to y if the sriov agent is required [y|n] [n] :
Enter a comma separated list of interface mappings for the Neutron ML2 sriov agent:
Enter a comma separated list of bridge mappings for the Neutron openvswitch plugin:
Enter a comma separated list of OVS bridge:interface pairs for the Neutron openvswitch plugin:
Enter a comma separated list of bridges for the Neutron OVS plugin in compute nodes. They must be included in os-neutron-ovs-bridge-mappings and os-neutron-ovs-bridge-interfaces.:
Enter interface with IP to override the default tunnel local_ip:
Enter comma separated list of subnets used for tunneling to make them allowed by IP filtering.:
Enter VXLAN UDP port number [4789] :

29.设置Dashboard服务,是否开启Https服务:

Would you like to set up Horizon communication over https [y|n] [n] :

30.配置对象存储服务,包括设备逻辑,zone,replicas,文件系统和块设备大小的配置:

Enter the Swift Storage devices e.g. /path/to/dev:
Enter the number of swift storage zones, MUST be no bigger than the number of storage devices configured [1] :
Enter the number of swift storage replicas, MUST be no bigger than the number of storage zones configured [1] :
Enter FileSystem type for storage nodes [xfs|ext4] [ext4] :
Enter the size of the storage device (eg. 2G, 2000M, 2000000K) [2G] :

31.是否启用Tempest服务:

Would you like to provision for demo usage and testing [y|n] [y] :
Would you like to configure Tempest (OpenStack test suite). Note that provisioning is only supported for all-in-one installations. [y|n] [n] :

32.设置Floating IP网段

Enter the network address for the floating IP subnet [172.24.4.224/28] :

33.设置测试镜像的名称,源地址,格式等配置:

Enter the name to be assigned to the demo image [cirros] :
Enter the location of an image to be loaded into Glance [http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-disk.img] :
Enter the format of the demo image [qcow2] :
Enter the name of a user to use when connecting to the demo image via ssh [cirros] :
Enter the name to be assigned to the uec image used for tempest [cirros-uec] :
Enter the location of a uec kernel to be loaded into Glance [http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-kernel] :
Enter the location of a uec ramdisk to be loaded into Glance [http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-initramfs] :
Enter the location of a uec disk image to be loaded into Glance [http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-disk.img] :
Would you like to configure the external ovs bridge [y|n] [y] :

34.设置Ceilometer,Aodh,Gnocchi服务:

Enter the password for Gnocchi DB access :
Confirm password :
Enter the password for the Gnocchi Keystone access :
Confirm password :
Enter the password for the Ceilometer Keystone access :
Confirm password :
Enter the Ceilometer service name. [ceilometer|httpd] [httpd] :
Enter the host for the MongoDB server [10.211.55.8] :
Enter the host for the Redis server [10.211.55.8] :
Enter the port of the redis server(s) [6379] :
Enter the password for the Aodh Keystone access :
Confirm password :

35.设置nagios用户的密码:

Enter the password for the nagiosadmin user :

36.最后一步,确认生成的配置是否符合期望,输入yes,并按回车键开始执行操作:

Packstack will be installed using the following configuration:
==============================================================
ssh-public-key: /root/.ssh/id_rsa.pub
default-password:
service-workers: %{::processorcount}
mariadb-install: y
......
aodh-ks-passwd: ********
nagios-passwd: ********
Proceed with the configuration listed above? (yes|no):

非交互式方式运行

使用下述命令生成一个answer file:

# packstack --gen-answer-file=my_file

使用vim打开文件,每个配置项都含有详细的说明:

[general]
# Path to a public key to install on servers. If a usable key has not
# been installed on the remote servers, the user is prompted for a
# password and this key is installed so the password will not be
# required again.
CONFIG_SSH_KEY=/root/.ssh/id_rsa.pub
# Default password to be used everywhere (overridden by passwords set
# for individual services or users).
CONFIG_DEFAULT_PASSWORD=
# The amount of service workers/threads to use for each service.
# Useful to tweak when you have memory constraints. Defaults to the
# amount of cores on the system.
CONFIG_SERVICE_WORKERS=%{::processorcount}
# Specify 'y' to install MariaDB. ['y', 'n']
CONFIG_MARIADB_INSTALL=y
# Specify 'y' to install OpenStack Image Service (glance). ['y', 'n']
CONFIG_GLANCE_INSTALL=y
......

例如,我们不希望配置MariaDB,只需要将CONFIG_MARIADB_INSTALL设置为n:

CONFIG_MARIADB_INSTALL=n

保存并退出my_file,在终端下运行以下命令指定相应的配置文件:

# packstack --answer-file=my_file

深入理解Packstack

Packstack的使用非常简单,关于如何使用的介绍就到此结束。接下来才是重点,我们要深入到Packstack的核心逻辑: Plugin,并且举例说明如何编写Plugin来完成对Packstack的功能扩展。

什么是Plugin

在前面两章对于PuppetOpenstack modules的介绍中,所有服务的部署工作实际是由每个modules完成的。 在使用Packstack的时候,我们发现Packstack支持大量的服务部署,例如:nova,glance,maridb,amqp等等。在其背后每个服务的配置项管理都是由plugin实现的,其路径是在: packstack/plugins,它看起来是这样的:

  • init.py

  • amqp_002.py

  • aodh_810.py

  • ...

  • trove_850.py

每个plugin的名称都是由服务名称+下划线+三位数字编码组成,那么这些数字有什么作用?

我们来看一下packstack代码入口packstack/installer/run_setup.py是怎么加载plugins的:

在主函数入口,可以看到第一步调用了loadPlugins函数来加载插件:

def main():
options = ""
try:
# Load Plugins
loadPlugins()
initPluginsConfig()

接着,我们跳转到了loadPlugins函数的定义,可以看到其中使用了sorted函数对由plugin文件组成的列表进行排序:

def loadPlugins():
"""
Load All plugins from ./plugins
"""
sys.path.append(basedefs.DIR_PLUGINS)
sys.path.append(basedefs.DIR_MODULES)
fileList = [f for f in os.listdir(basedefs.DIR_PLUGINS) if f[0] != "_"]
fileList = sorted(fileList, cmp=plugin_compare) #使用plugin_compare函数作为key进行排序
for item in fileList:
# Looking for files that end with ###.py, example: a_plugin_100.py
match = re.search("^(.+\_\d\d\d)\.py$", item)
if match:
try:
moduleToLoad = match.group(1)
logging.debug("importing module %s, from file %s", moduleToLoad, item)
moduleobj = __import__(moduleToLoad)
moduleobj.__file__ = os.path.join(basedefs.DIR_PLUGINS, item)
globals()[moduleToLoad] = moduleobj
checkPlugin(moduleobj)
controller.addPlugin(moduleobj)
except:
logging.error("Failed to load plugin from file %s", item)
logging.error(traceback.format_exc())
raise Exception("Failed to load plugin from file %s" % item)

查看函数plugin_compare的定义,我们终于找到了关键,plugin_compare使用每个plugin文件尾缀的三位数字用于排序比较:

def plugin_compare(x, y):
"""
Used to sort the plugin file list
according to the number at the end of the plugin module
"""
x_match = re.search(".+\_(\d\d\d)", x)
x_cmp = x_match.group(1)
y_match = re.search(".+\_(\d\d\d)", y)
y_cmp = y_match.group(1)
return int(x_cmp) - int(y_cmp)

在了解了plugin的加载顺序后,我们再看看Plugin的代码结构。实际上,每个plugin的代码结构是一致的,由两个函数组成:

  • initConfig(controller) 用于初始化Plugin的配置,主要是参数和参数组。

  • initSequences(controller) 用于定义该plugin执行的任务。

在这些plugin中,必然会有一些与众不同的plugin,比如说第一个被加载的plugin,,倒数第二个被加载的plugin,以及最后一个被加载的plugin:

  • prescript_000.py是第一个被加载的plugin,顾名思义它提供了一些全局的初始化设置,比如ssh public key,default_password,workers的进程数量,是否开启各个OpenStack服务的设置等等,同时它会在被管理的主机上执行一些预备任务:生成authorized_keys文件,安装并开启epel源和rdo源,安装puppet软件包依赖和module依赖等等。

  • puppet_950.py是一个重要的plugin,顾名思义它提供了与puppet相关的任务,例如:生成最终的manifest文件,拷贝puppet modules到指定主机,生成hieradata文件,以standalone方式运行puppet:执行puppet apply,获取puppet运行中的输出等等。

  • postscript_951.py是最后一个呗加载的plugin,它只做了一件事情,就是运行Tempest跑测试任务。

动手写一个Plugin

在了解了plugin的运行机制后,我们来动手写一个plugin,我们称之为NOOP:这是一个空Plugin,默认只输出一行信息: NOOP Plugin.

创建一个Plugin文件

在packstack/plugins目录下,我们创建一个plugin文件: noop_840.py。

设置Import和Plugin定义

# -*- coding: utf-8 -*-
"""
Installs and configures NOOP
"""
from packstack.installer import basedefs
from packstack.installer import validators
from packstack.installer import processors
from packstack.installer import utils
from packstack.modules.common import filtered_hosts
from packstack.modules.documentation import update_params_usage
from packstack.modules.ospluginutils import generate_ssl_cert
# ------------- NOOP Packstack Plugin Initialization --------------
PLUGIN_NAME = "NOOP"
PLUGIN_NAME_COLORED = utils.color_text(PLUGIN_NAME, 'blue')

每个Plugin的import可能会有所不同,但大多数都会用到packstack.installer和packstack.modules。

此外,这里有两个和plugin相关的变量:

变量

说明

PLUGIN_NAME

plugin名称,全部大写字母

PLUGIN_NAME_COLORED

plugin显示的颜色,默认使用blue即可。

定义Plugin的配置信息

我们定义一个initConfig函数,其中包含了两个变量:

  • params

  • group

def initConfig(controller):
params = [
{"CMD_OPTION": "enable-noop",
"USAGE": "To set up noop service set this to 'y'",
"PROMPT": "Would you like to set up noop service",
"OPTION_LIST": ["y", "n"],
"VALIDATORS": [validators.validate_options],
"DEFAULT_VALUE": "n",
"MASK_INPUT": False,
"LOOSE_VALIDATION": True,
"CONF_NAME": "CONFIG_ENABLE_NOOP",
"USE_DEFAULT": False,
"NEED_CONFIRM": False,
"CONDITION": False},
]
group = {"GROUP_NAME": "NOOP",
"DESCRIPTION": "NOOP Config parameters",
"PRE_CONDITION": "CONFIG_NOOP_INSTALL",
"PRE_CONDITION_MATCH": "y",
"POST_CONDITION": False,
"POST_CONDITION_MATCH": True}
controller.addGroup(group, params)

params是NOOP plugin定义的配置项,每个配置项的数据类型是字典。这些配置项可以作为顺序执行的一部分,或者作为Puppet模板的变量。

选项

说明

CMD_OPTION

被命令行使用的选项名称

USAGE

选项的使用说明,同时作为answer file的注释

PROMPT

交互模式下给用户的提示

OPTION_LIST

可选值列表,可以设置为[]或移除该选项,表示对选项值无限制

VALIDATORS

验证器函数列表,用于检查输入是否符合要求

DEFAULT_VALUE

选项的默认值

PROCESSORS

处理器函数列表,处理器函数对用户的输入做了处理,比如processors.process_host将主机名转变为IP地址等等

MASK_INPUT

是否隐藏用户的输入,如password

LOOSE_VALIDATION

若为true,则即使验证器返回为false,仍然使用用户输入的选项值

CONF_NAME

在answer file中的配置项名称,你同时可以在controller.CONF dict中找到

USE_DEFAULT

若为true,在交互模式下,将不会要求用户输入此变量的值,而直接DEFAULT_VALUE

NEED_CONFIRM

若为true,则要求用户确认其输入(比如password)

CONDITION

enable/disable该选项的条件,总是设置为False即可

DEPRECATES

弃用的CONF_NAME选项列表,通常在新版本时使用

group表示组的概念,在Packstack中,会把相关的配置项分组,这样就可以通过组的方式来管理和使用。group的数据类型是字典:

选项

说明

GROUP_NAME

组名,全局唯一

DESCRIPTION

组的描述,在命令行的帮助命令下会显示此信息

PRE_CONDITION

前提条件,可以是一个配置项的值或函数的返回值匹配预期。若为False,那么该配置组处于启用状态

PRE_CONDITION_MATCH

前提条件的预期匹配值

POST_CONDITION

配置组所有参数是正确的后置条件,若设置为False,则表示不做检查。通常设置为False

POST_CONDITION_MATCH

后置条件的预期匹配值,通常设置为True

这里最重要的是PRE_CONDITION和PRE_CONDITION_MATCH,可能有些晦涩,我们以部署Cinder服务为例,只有当PRE_CONDITION中的变量CONFIG_CINDER_INSTALL为"y"时,才会显示"Cinder"组的配置选项:

{"GROUP_NAME": "CINDER",
"DESCRIPTION": "Cinder Config parameters",
"PRE_CONDITION": "CONFIG_CINDER_INSTALL",
"PRE_CONDITION_MATCH": "y",
"POST_CONDITION": False,
"POST_CONDITION_MATCH": True
}

最后一步,把这些已定义的选项添加controller的组中:

controller.addGroup(group, params)

定义函数执行顺序

前面我们说到每个plugin除了定义一组相关的选项之外,还会执行一些任务,比如:从用户给定的变量值来渲染template,从而生成该服务的Puppet manifest文件。这些任务是由一个个函数组成,函数之间有执行的先后顺序,这个顺序就是由initSeqeuence函数来决定。

我们假设NOOP服务的安装需要数据库服务MariaDB,以及在Keystone中创建endpoint等操作:

def initSequences(controller):
if controller.CONF['CONFIG_NOOP_INSTALL'] != 'y':
return
steps = [{'title': 'Adding MariaDB manifest entries',
'functions': [create_mariadb_manifest]},
{'title': 'Adding NOOP manifest entries',
'functions': [create_manifest]},
{'title': 'Adding NOOP Keystone manifest entries',
'functions': [create_keystone_manifest]}]
controller.addSequence('Installing NOOP service', [], [], steps)

setps是一个列表,其中每个元素的数据类型都是字典,它的格式如下:

选项

说明

title

函数的简单描述信息

functions

函数列表

最后,我们调用controller.addSequence()方法把plugin的steps添加到将要被执行的序列列表中。 通常情况下,第二个和第二个选项为空。

生成manifest文件

在讲生成manifest文件之前,我们需要花些时间来了解packstack的templates,在当前版本中packstack的templates的路径是packstack/puppet/templates,数量已经从几十个削减为3个:

  • controller

  • compute

  • network

我们以controller为例,我们选取其中的代码片段:

stage { "init": before => Stage["main"] }
Exec { timeout => hiera('DEFAULT_EXEC_TIMEOUT') }
Package { allow_virtual => true }
class {'::packstack::prereqs':
stage => init,
}
include ::firewall
if hiera('CONFIG_NTP_SERVERS', '') != '' {
include '::packstack::chrony'
}
include '::packstack::amqp'
include '::packstack::mariadb'
if hiera('CONFIG_MARIADB_INSTALL') == 'y' {
include 'packstack::mariadb::services'
} else {
include 'packstack::mariadb::services_remote'
}

我们可以发现,这实质上是一个manifest文件(.pp),而非template文件(.erb),所有class或define的include不再使用erb模板的方式来渲染,而是使用了简单的条件判断来做选择。

每个函数都是接受固定的两个参数:

  • config

  • messages