Openstack之路计算服务Nova

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Nova的概述

Nova是Openstack云中的计算组织控制器。支持Openstack云中实例（Instances）生命周期的所有活动都由Nova处理。这样使得Nova成为一个负责管理计算资源、网络、认证、所需可扩展性的平台。但是Nova自身并没有提供任何虚拟化能力，相反它使用Libvirt API来与被支持的Hypervisors交互。Nova通过一个与Amazon Web Services（AWS）EC2 API兼容的Web Services API来对外提供服务。

Nova的组件

  • Nova-API

Nova-API是整个Nova组件的门户，所有对Nova的请求都首先由Nova-API来处理，接收到外部的请求后通过Message Queue将请求发送给其它的服务组件。

  • Nova-Scheduler

Nova-Scheduler负责决策虚拟机创建在那台主机(计算节点)上。

  • Nova-Compute

Nova-Compute处理管理实例生命周期，通过Message Queue接收实例生命周期管理的请求，并承担操作工作。

  • Nova-Conductor

Nova-Compute需要获取和更新数据库中Instance的信息，但是Nova-Compute并不会直接访问数据库，而是通过Nova-Conductor实现数据的访问。这样做有两个显著好处，其一更高的系统安全性，其二更好的系统伸缩性。

在Openstack的早期版本中，Nova-Compute可以直接访问数据库，但这样存在非常大的安全隐患。因为Nova-Compute这个服务是部署在计算节点上的，为了能够访问控制节点上的数据库，就必须在计算节点的/etc/nova/nova.conf中配置访问数据库的连接信息，试想任意一个计算节点被黑客入侵，都会导致部署在控制节点上的数据库面临极大风险。这样就避免了Nova-Compute直接访问数据库，增加了系统的安全性。

Nova-Conductor将Nova-Compute与数据库解耦之后还带来另一个好处就是提高了Nova的伸缩性。Nova-Compute与Conductor是通过消息中间件交互的，这种松散的架构允许配置多个Nova-Conductor实例，在一个大规模的Openstack部署环境里，管理员可以通过增加Nova-Conductor的数量来应对日益增长的计算节点对数据库的访问。

Nova的工作流程

技术分享图片

Nova实例化流程

  1. 首先用户执行Nova Client提供的用于创建虚拟机的指令。
  2. Nova-API监听到来自于Nova Client的HTTP请求，并将这些请求转换为AMQP消息之后加入消息队列Queue。
  3. 通过消息队列Queue调用Nova-Conductor。
  4. Nova-Conductor从Queue接收到虚拟机实例化请求消息后，进行一些准备工作，例如：汇总HTTP请求中所需要实例化的虚拟机参数。
  5. Nova-Conductor通过Queue告诉Nova-Scheduler去选择一个合适的Compute Node来创建虚拟机，此时Nova-Scheduler会读取数据库的内容。
  6. Nova-Conductor从Nova-Scheduler得到了合适的Compute Node的信息后，再通过Queue来通知Nova-Compute实现虚拟机的创建。
  7. 从虚拟机实例化的过程可以看出，Nova中最重要的4个服务之间的通信都是通过Queue来实现的，这符合松耦合的实现方式。

安装配置控制节点

Nova的安装

  • 创建数据库服务的凭据以及API Endpoints
MariaDB [(none)]> create database nova;
Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> create database nova_api;
Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| glance             |
| information_schema |
| keystone           |
| mysql              |
| nova               |
| nova_api           |
| performance_schema |
+--------------------+
7 rows in set (0.00 sec)

MariaDB [(none)]> grant all on nova.* to ‘nova‘@‘localhost‘ identified by ‘nova‘;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> grant all on nova.* to ‘nova‘@‘%‘ identified by ‘nova‘;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> grant all on nova_api.* to ‘nova‘@‘localhost‘ identified by ‘nova‘;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> grant all on nova_api.* to ‘nova‘@‘%‘ identified by ‘nova‘;
Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> exit
Bye
  • 获得admin凭证来获取只有管理员能执行的命令的访问权限
[[email protected] ~]# source admin-openrc
  • 要创建服务证书，完成这些步骤

创建nova用户

[[email protected] ~]# openstack user create --domain default --password-prompt nova
User Password:
Repeat User Password:
+---------------------+----------------------------------+
| Field               | Value                            |
+---------------------+----------------------------------+
| domain_id           | default                          |
| enabled             | True                             |
| id                  | 99f1a510951741419024f5d19227046c |
| name                | nova                             |
| password_expires_at | None                             |
+---------------------+----------------------------------+

给nova用户添加admin角色

[[email protected] ~]# openstack role add --project service --user nova admin

创建Nova服务实体

[[email protected] ~]# openstack service create --name nova --description "OpenStack Compute" compute
+-------------+----------------------------------+
| Field       | Value                            |
+-------------+----------------------------------+
| description | OpenStack Compute                |
| enabled     | True                             |
| id          | a3c8c4b6954f4e12a197e4a480d6bf53 |
| name        | nova                             |
| type        | compute                          |
+-------------+----------------------------------+

创建Compute服务API端点

[[email protected] ~]# openstack endpoint create --region RegionOne compute public http://192.168.56.11:8774/v2.1/%\(tenant_id\)s
+--------------+----------------------------------------------+
| Field        | Value                                        |
+--------------+----------------------------------------------+
| enabled      | True                                         |
| id           | e1609436807842caae0caf293ae61882             |
| interface    | public                                       |
| region       | RegionOne                                    |
| region_id    | RegionOne                                    |
| service_id   | a3c8c4b6954f4e12a197e4a480d6bf53             |
| service_name | nova                                         |
| service_type | compute                                      |
| url          | http://192.168.56.11:8774/v2.1/%(tenant_id)s |
+--------------+----------------------------------------------+

[[email protected] ~]# openstack endpoint create --region RegionOne compute internal http://192.168.56.11:8774/v2.1/%\(tenant_id\)s
+--------------+----------------------------------------------+
| Field        | Value                                        |
+--------------+----------------------------------------------+
| enabled      | True                                         |
| id           | 2f5db2a54b5b49b7aa8aa517e693778a             |
| interface    | internal                                     |
| region       | RegionOne                                    |
| region_id    | RegionOne                                    |
| service_id   | a3c8c4b6954f4e12a197e4a480d6bf53             |
| service_name | nova                                         |
| service_type | compute                                      |
| url          | http://192.168.56.11:8774/v2.1/%(tenant_id)s |
+--------------+----------------------------------------------+

[[email protected] ~]# openstack endpoint create --region RegionOne compute admin http://192.168.56.11:8774/v2.1/%\(tenant_id\)s
+--------------+----------------------------------------------+
| Field        | Value                                        |
+--------------+----------------------------------------------+
| enabled      | True                                         |
| id           | 7b6d8e440ac14266b42508c9f6ca892b             |
| interface    | admin                                        |
| region       | RegionOne                                    |
| region_id    | RegionOne                                    |
| service_id   | a3c8c4b6954f4e12a197e4a480d6bf53             |
| service_name | nova                                         |
| service_type | compute                                      |
| url          | http://192.168.56.11:8774/v2.1/%(tenant_id)s |
+--------------+----------------------------------------------+

安装Nova相关软件包

[[email protected] ~]# yum -y install openstack-nova-api openstack-nova-conductor openstack-nova-console openstack-nova-novncproxy openstack-nova-scheduler
[[email protected] ~]# rpm -qa openstack-nova-api openstack-nova-conductor openstack-nova-console openstack-nova-novncproxy openstack-nova-scheduler
openstack-nova-conductor-14.0.10-1.el7.noarch
openstack-nova-novncproxy-14.0.10-1.el7.noarch
openstack-nova-api-14.0.10-1.el7.noarch
openstack-nova-scheduler-14.0.10-1.el7.noarch
openstack-nova-console-14.0.10-1.el7.noarch

Nova的配置

  • 编辑/etc/nova/nova.conf文件并完成下面的操作
[[email protected] ~]# cp -a /etc/nova/nova.conf /etc/nova/nova.conf_$(date +%F)
[[email protected] ~]# vim /etc/nova/nova.conf

在[DEFAULT]部分，只启用计算和元数据API

[DEFAULT]
......
3052 enabled_apis = osapi_compute,metadata

在[api_database]和[database]部分，配置数据库的连接

[api_database]
......
3661 connection = mysql+pymysql://nova:[email protected]/nova_api

[database]
......
4678 connection = mysql+pymysql://nova:[email protected]/nova

在[DEFAULT]部分，配置RabbitMQ消息队列访问权限

[DEFAULT]
......
3602 transport_url = rabbit://openstack:[email protected]

在[DEFAULT]和[keystone_authtoken]部分，配置认证服务访问

[DEFAULT]
......
14 auth_strategy = keystone

[keystone_authtoken]
......
5431 auth_uri = http://192.168.56.11:5000
5432 auth_url = http://192.168.56.11:35357
5433 memcached_servers = 192.168.56.11:11211
5434 auth_type = password
5435 project_domain_name = Default
5436 user_domain_name = Default
5437 project_name = service
5438 username = nova
5439 password = nova

在 [DEFAULT]部分，启用网络服务支持

[DEFAULT]
......
2062 use_neutron = True
3266 firewall_driver = nova.virt.firewall.NoopFirewallDriver

在[vnc]部分，配置VNC代理使用控制节点的管理接口IP地址

[VNC]
......
8326 vncserver_listen = 0.0.0.0
8338 vncserver_proxyclient_address = 192.168.56.11

在[glance]区域，配置镜像服务API的位置

[glance]
......
4815 api_servers = http://192.168.56.11:9292

在[oslo_concurrency]部分，配置锁路径

[oslo_concurrency]
......
6707 lock_path = /var/lib/nova/tmp
  • 同步Compute数据库，可以忽略警告信息
[[email protected] ~]# su -s /bin/sh -c "nova-manage api_db sync" nova
[[email protected] ~]# su -s /bin/sh -c "nova-manage db sync" nova
[[email protected] ~]# mysql -unova -pnova -e "use nova;show tables;"
[[email protected] ~]# mysql -unova -pnova -e "use nova_api;show tables;"
  • 启动Compute服务，并将其设置为随系统启动
[[email protected] ~]# systemctl enable openstack-nova-api.service openstack-nova-consoleauth.service openstack-nova-scheduler.service openstack-nova-conductor.service openstack-nova-novncproxy.service

[[email protected] ~]# systemctl start openstack-nova-api.service openstack-nova-consoleauth.service openstack-nova-scheduler.service openstack-nova-conductor.service openstack-nova-novncproxy.service

[[email protected] ~]# systemctl status openstack-nova-api.service
[[email protected] ~]# systemctl status openstack-nova-consoleauth.service
[[email protected] ~]# systemctl status openstack-nova-scheduler.service
[[email protected] ~]# systemctl status openstack-nova-conductor.service
[[email protected] ~]# systemctl status openstack-nova-novncproxy.service

Nova验证操作

[[email protected] ~]# openstack host list
+-------------+-------------+----------+
| Host Name   | Service     | Zone     |
+-------------+-------------+----------+
| linux-node1 | conductor   | internal |
| linux-node1 | consoleauth | internal |
| linux-node1 | scheduler   | internal |
+-------------+-------------+----------+

[[email protected] ~]# openstack compute service list
+----+------------------+-------------+----------+---------+-------+----------------------------+
| ID | Binary           | Host        | Zone     | Status  | State | Updated At                 |
+----+------------------+-------------+----------+---------+-------+----------------------------+
|  1 | nova-conductor   | linux-node1 | internal | enabled | up    | 2018-01-16T07:09:13.000000 |
|  2 | nova-consoleauth | linux-node1 | internal | enabled | up    | 2018-01-16T07:09:12.000000 |
|  3 | nova-scheduler   | linux-node1 | internal | enabled | up    | 2018-01-16T07:09:17.000000 |
+----+------------------+-------------+----------+---------+-------+----------------------------+

安装配置计算节点

Nova-Compute的安装

  • 添加Openstack仓库，安装Newton版
[[email protected] ~]# yum -y install centos-release-openstack-newton
[[email protected] ~]# rpm -qa centos-release-openstack-newton
centos-release-openstack-newton-1-2.el7.noarch
  • 安装Openstack客户端
[[email protected] ~]# yum -y install python-openstackclient openstack-selinux
[[email protected] ~]# rpm -qa python-openstackclient openstack-selinux
python-openstackclient-3.2.1-1.el7.noarch
openstack-selinux-0.8.11-1.el7.noarch
  • 安装Nova-Compute相关软件包
[[email protected] ~]# yum -y install openstack-nova-compute
[[email protected] ~]# rpm -qa openstack-nova-compute
openstack-nova-compute-14.0.10-1.el7.noarch

Nova-Compute的配置

  • 编辑/etc/nova/nova.conf文件并完成下面的操作
[[email protected] ~]# cp -a /etc/nova/nova.conf /etc/nova/nova.conf_$(date +%F)
[[email protected] ~]# vim /etc/nova/nova.conf

在[DEFAULT]部分，只启用计算和元数据API

[DEFAULT]
......
3052 enabled_apis = osapi_compute,metadata

在[DEFAULT]部分，配置RabbitMQ消息队列访问权限

[DEFAULT]
......
3601 transport_url = rabbit://openstack:[email protected]

在[DEFAULT]和[keystone_authtoken]部分，配置认证服务访问

[DEFAULT]
......
14 auth_strategy = keystone

[keystone_authtoken]
......
5431 auth_uri = http://192.168.56.11:5000
5432 auth_url = http://192.168.56.11:35357
5433 memcached_servers = 192.168.56.11:11211
5434 auth_type = password
5435 project_domain_name = Default
5436 user_domain_name = Default
5437 project_name = service
5438 username = nova
5439 password = nova

在[DEFAULT]部分，启用网络服务支持

[DEFAULT]
......
2062 use_neutron = True
3266 firewall_driver = nova.virt.firewall.NoopFirewallDriver

在[vnc]部分，启用并配置远程控制台访问

[vnc]
......
8303 enabled = true
8326 vncserver_listen = 0.0.0.0
8338 vncserver_proxyclient_address = 192.168.56.12
8357 novncproxy_base_url=http://192.168.56.11:6080/vnc_auto.html

在[glance]区域，配置镜像服务API的位置

[glance]
......
4815 api_servers = http://192.168.56.11:9292

在[oslo_concurrency]部分，配置锁路径

[oslo_concurrency]
......
6707 lock_path = /var/lib/nova/tmp

Nava-Compute验证操作

  • 确定您的计算节点是否支持虚拟机的硬件加速
[[email protected] ~]# egrep -c ‘(vmx|svm)‘ /proc/cpuinfo
1

如果这个命令返回了one or greater的值，那么你的计算节点支持硬件加速且不需要额外的配置。

如果这个命令返回了zero值，那么你的计算节点不支持硬件加速。你必须配置libvirt来使用QEMU去代替KVM。

  • 启动计算服务及其依赖，并将其配置为随系统自动启动
[[email protected] ~]# systemctl enable libvirtd.service openstack-nova-compute.service

[[email protected] ~]# systemctl start libvirtd.service openstack-nova-compute.service

[[email protected] ~]# systemctl status libvirtd.service
[[email protected] ~]# systemctl status openstack-nova-compute.service
  • 获得admin凭证来获取只有管理员能执行的命令的访问权限
[[email protected] ~]# source admin-openrc
  • 列出服务组件，以验证是否成功启动并注册了每个进程
[[email protected] ~]# openstack host list
+-------------+-------------+----------+
| Host Name   | Service     | Zone     |
+-------------+-------------+----------+
| linux-node1 | conductor   | internal |
| linux-node1 | consoleauth | internal |
| linux-node1 | scheduler   | internal |
| linux-node2 | compute     | nova     |
+-------------+-------------+----------+

[[email protected] ~]# openstack compute service list
+----+------------------+-------------+----------+---------+-------+----------------------------+
| ID | Binary           | Host        | Zone     | Status  | State | Updated At                 |
+----+------------------+-------------+----------+---------+-------+----------------------------+
|  1 | nova-conductor   | linux-node1 | internal | enabled | up    | 2018-01-16T07:04:43.000000 |
|  2 | nova-consoleauth | linux-node1 | internal | enabled | up    | 2018-01-16T07:04:42.000000 |
|  3 | nova-scheduler   | linux-node1 | internal | enabled | up    | 2018-01-16T07:04:47.000000 |
|  6 | nova-compute     | linux-node2 | nova     | enabled | up    | 2018-01-16T07:04:46.000000 |
+----+------------------+-------------+----------+---------+-------+----------------------------+

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