Openstack之路镜像服务Glance

Posted 2020-10-21

Glance的概述

Glance是为虚拟机的创建提供镜像的服务，我们基于Openstack是构建基本的IaaS平台对外提供虚拟机，而虚拟机在创建时必须为选择需要安装的操作系统，Glance服务就是为该选择提供不同的操作系统镜像。

Glance的组件

• Glance-API

主要用来响应各种REST请求然后通过其它模块（主要是glance-registry组件和后端存储接口）完成镜像的上传、删除、查询等操作。可以简单的再分为两部分：一层中间件，它主要是做一些对请求的解析工作（如分析出版本号）， 另外一部分提供实际的服务（如与镜像上传下载的后端存储接×××互）。默认绑定端口是9292。

• Glance-Registry

镜像注册服务用于提供镜像元数据的REST接口。主要工作是存储或者获取镜像的元数据，与mysql数据库进行交互。也可以简单的再细分为两部分，API和具体的Server。元数据是指镜像相关的一些信息（如id，size， status，location，checksum，min_disk，min_ram，owner等）真正的镜像数据保存在实际所使用的后端存储里（如Swift，S3，Filesystem等）。默认绑定的端口是9191。

• Image Store

严格来说Image Store不属于Glance的组件，这里把它单独分出来只是为了方便理解，它只是一个接口层，提供镜像存储和查询的接口。具体的实现则需要外部存储（Swift，S3）的支持。

Glance的工作流程

Glance安装配置

Glance的安装

• 创建一个数据库、服务凭证和API端点

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

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

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

MariaDB [(none)]> grant all on glance.* to ‘glance‘@‘%‘ identified by ‘glance‘;
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glance用户

[[email protected] ~]# openstack user create --domain default --password-prompt glance
User Password:
Repeat User Password:
+---------------------+----------------------------------+
| Field               | Value                            |
+---------------------+----------------------------------+
| domain_id           | default                          |
| enabled             | True                             |
| id                  | bd7a2a0f75384a33a4abb349c6840bc8 |
| name                | glance                           |
| password_expires_at | None                             |
+---------------------+----------------------------------+

添加admin角色到glance用户和service项目上

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

• 创建glance服务实体

[[email protected] ~]# openstack service create --name glance --description "OpenStack Image" image
+-------------+----------------------------------+
| Field       | Value                            |
+-------------+----------------------------------+
| description | OpenStack Image                  |
| enabled     | True                             |
| id          | 8188d497252d44f59cb2e8e0c4017055 |
| name        | glance                           |
| type        | image                            |
+-------------+----------------------------------+

• 创建镜像服务的API端点

[[email protected] ~]# openstack endpoint create --region RegionOne image public http://192.168.56.11:9292
+--------------+----------------------------------+
| Field        | Value                            |
+--------------+----------------------------------+
| enabled      | True                             |
| id           | d52e57b312ab4fadb2f84222660f01a8 |
| interface    | public                           |
| region       | RegionOne                        |
| region_id    | RegionOne                        |
| service_id   | 8188d497252d44f59cb2e8e0c4017055 |
| service_name | glance                           |
| service_type | image                            |
| url          | http://192.168.56.11:9292        |
+--------------+----------------------------------+

[[email protected] ~]# openstack endpoint create --region RegionOne image internal http://192.168.56.11:9292
+--------------+----------------------------------+
| Field        | Value                            |
+--------------+----------------------------------+
| enabled      | True                             |
| id           | f44c4a6fb1d64140bded5f220cbad948 |
| interface    | internal                         |
| region       | RegionOne                        |
| region_id    | RegionOne                        |
| service_id   | 8188d497252d44f59cb2e8e0c4017055 |
| service_name | glance                           |
| service_type | image                            |
| url          | http://192.168.56.11:9292        |
+--------------+----------------------------------+

[[email protected] ~]# openstack endpoint create --region RegionOne image admin http://192.168.56.11:9292
+--------------+----------------------------------+
| Field        | Value                            |
+--------------+----------------------------------+
| enabled      | True                             |
| id           | f1b9538274f54cae8b0349bfbf17dca0 |
| interface    | admin                            |
| region       | RegionOne                        |
| region_id    | RegionOne                        |
| service_id   | 8188d497252d44f59cb2e8e0c4017055 |
| service_name | glance                           |
| service_type | image                            |
| url          | http://192.168.56.11:9292        |
+--------------+----------------------------------+

• 安装Glance相关软件包

[[email protected] ~]# yum -y install openstack-glance
[[email protected] ~]# rpm -qa openstack-glance
openstack-glance-13.0.0-1.el7.noarch

Glance的配置

• 编辑/etc/glance/glance-api.conf文件，并完成如下更改

[[email protected] ~]# cp -a /etc/glance/glance-api.conf /etc/glance/glance-api.conf_$(date +%F)
[[email protected] ~]# vim /etc/glance/glance-api.conf

在[database]部分，配置数据库访问

[database]
......
1748 connection = mysql+pymysql://glance:[email protected]/glance

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

[keystone_authtoken]
......
3179 auth_uri = http://192.168.56.11:5000
3180 auth_url = http://192.168.56.11:35357
3181 memcached_servers = 192.168.56.11:11211
3182 auth_type = password
3183 project_domain_name = Default
3184 user_domain_name = Default
3185 project_name = service
3186 username = glance
3187 password = glance

[paste_deploy]
......
3990 flavor = keystone

在[glance_store]部分，配置本地文件系统存储和镜像文件位置

[glance_store]
......
1864 stores = file,http
1896 default_store = file
2196 filesystem_store_datadir = /var/lib/glance/images

• 编辑/etc/glance/glance-registry.conf文件，并完成如下更改

[[email protected] ~]# cp -a /etc/glance/glance-registry.conf /etc/glance/glance-registry.conf_$(date +%F)
[[email protected] ~]# vim /etc/glance/glance-registry.conf

在[database]部分，配置数据库访问

[database]
......
1038 connection = mysql+pymysql://glance:[email protected]/glance

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

[keystone_authtoken]
......
1128 auth_uri = http://192.168.56.11:5000
1129 auth_url = http://192.168.56.11:35357
1130 memcached_servers = 192.168.56.11:11211
1131 auth_type = password
1132 project_domain_name = Default
1133 user_domain_name = Default
1134 project_name = service
1135 username = glance
1136 password = glance

[paste_deploy]
......
1910 flavor = keystone

• 写入镜像服务数据库，可以忽略警告信息

[[email protected] ~]# su -s /bin/sh -c "glance-manage db_sync" glance
[[email protected] ~]# mysql -uglance -pglance -e "use glance;show tables;"

• 启动镜像服务glance-api、glance-registry，并配置为开机自启

[[email protected] ~]# systemctl enable openstack-glance-api.service
[[email protected] ~]# systemctl start openstack-glance-api.service
[[email protected] ~]# systemctl status openstack-glance-api.service

[[email protected] ~]# systemctl enable openstack-glance-registry.service
[[email protected] ~]# systemctl start openstack-glance-registry.service
[[email protected] ~]# systemctl status openstack-glance-registry.service

Glance验证操作

使用CirrOS对镜像服务进行验证，CirrOS是一个小型的Linux镜像可以用来帮助你进行Openstack部署测试。

• 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

• 下载CirrOS源镜像

[[email protected] ~]# wget http://download.cirros-cloud.net/0.3.4/cirros-0.3.4-x86_64-disk.img
[[email protected] ~]# ls -l cirros-0.3.4-x86_64-disk.img
-rw-r--r-- 1 root root 13287936 May  8  2015 cirros-0.3.4-x86_64-disk.img

• 使用qcow2磁盘格式，bare容器格式上传镜像到镜像服务并设置公共可见，这样所有的项目都可以访问它

[[email protected] ~]# openstack image create "cirros" --file cirros-0.3.4-x86_64-disk.img --disk-format qcow2 --container-format bare --public
+------------------+------------------------------------------------------+
| Field            | Value                                                |
+------------------+------------------------------------------------------+
| checksum         | ee1eca47dc88f4879d8a229cc70a07c6                     |
| container_format | bare                                                 |
| created_at       | 2018-01-15T07:07:12Z                                 |
| disk_format      | qcow2                                                |
| file             | /v2/images/b4223969-0add-4641-8317-18e2b1d25b54/file |
| id               | b4223969-0add-4641-8317-18e2b1d25b54                 |
| min_disk         | 0                                                    |
| min_ram          | 0                                                    |
| name             | cirros                                               |
| owner            | 71c9b608e79546f4b90f710fea475de3                     |
| protected        | False                                                |
| schema           | /v2/schemas/image                                    |
| size             | 13287936                                             |
| status           | active                                               |
| tags             |                                                      |
| updated_at       | 2018-01-15T07:07:13Z                                 |
| virtual_size     | None                                                 |
| visibility       | public                                               |
+------------------+------------------------------------------------------+

• 确认镜像的上传并验证属性

[[email protected] ~]# openstack image list
+--------------------------------------+--------+--------+
| ID                                   | Name   | Status |
+--------------------------------------+--------+--------+
| b4223969-0add-4641-8317-18e2b1d25b54 | cirros | active |
+--------------------------------------+--------+--------+