OpenStack components --Horizon Web interface management services

1.horizon Introduction

Understanding horizon

Openstack Horizon to provide a front end WEB management interface (UI Service) service by DashBoard Horizone provided, an administrator can manage the whole cloud Openstack WEB through the UI, and visually see the results of various operations of the operating state.

DashBoard relationship with other components

Start the client browser, in the address bar

http://Horizone_server_ip/dashboard

2. Regional (Region)

1) the geographical concept, can be understood as a separate data centers, each defined area has its own independent Endpoint;

2) between the regions are completely isolated, but the same shared among a plurality of regions and Keystone Dashboard (Openstack currently not supported in the Dashboard plurality of areas);

3) In addition to providing isolation function, design area of focus more on the concept of geographic location, the user can choose to deploy their own services from their own area update, select a different area mainly on account of that region closer to their own, such as a user in the United States They can choose from more recent area of the United States;

4) concept proposed by the Amazon region is in the AWS, mainly to resolve the fault tolerance and reliability;

3. availability zone (Availability Zone)

. 1) is re-sliced AZ Region within the range, for example, a server on the rack into one AZ, AZ division in order to improve the disaster recovery capability is to provide an inexpensive and service isolation;

2) AZ mainly to address availability issues through redundancy in the Amazon statement, Instance means that the user is not available for all AZ in the same Instance did not show up is not available;

. 3) is a conceptual AZ visible to the user, and optionally, physical separation, a unavailable AZ AZ not affect the other, when creating the user can choose to create the Instance that the AZ;

4.Host Aggreates

一组具有共同属性的节点集合，如以CPU作为区分类型的一个属性，以磁盘（SSD\SAS\SATA）作为区分类型的一个属性，以OS（Windows\Linux）为作区分类型的一个属性；

5.Cell

nova为了增加横向扩展以及分布式、大规模（地理位置级别）部署的能力，同时又不增加数据库和消息中间件的复杂度，引入了cell的概念，并引入了nova-cell服务。

1）主要是用来解决OpenStack的扩展性和规模瓶颈；

2）每个Cell都有自己独立的DB和AMQP，不与其他模块共用DB和AMQP,解决了大规模环境中DB和AMQP的瓶颈问题；

3）Cell实现了树形结构（通过消息路由）和分级调度（过滤算法和权重算法），Cell之间通过RPC通讯，解决了扩展性问题；

6.配置dashboard服务

1）安装相关软件包

    yum install openstack-dashboard -y

2）修改配置文件

vim /etc/openstack-dashboard/local_settings

ALLOWED_HOSTS = ['horizon.example.com', 'localhost','*']
...
OPENSTACK_API_VERSIONS = {
    "identity": 3,
    "image": 2,
    "volume": 2,
    "compute": 2,
}
...
OPENSTACK_KEYSTONE_MULTIDOMAIN_SUPPORT = True
...
OPENSTACK_KEYSTONE_DEFAULT_DOMAIN = 'Default'
...
SESSION_ENGINE = 'django.contrib.sessions.backends.cache'
...
CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
        'LOCATION': 'node1:11211',
    },
}
...
OPENSTACK_HOST = "node1"
...
OPENSTACK_KEYSTONE_URL = "http://%s:5000/v3" % OPENSTACK_HOST
...
OPENSTACK_KEYSTONE_DEFAULT_ROLE = "user"
...
OPENSTACK_NEUTRON_NETWORK = {
    'enable_router': True,
    'enable_quotas': True,
    'enable_ipv6': True,
    'enable_distributed_router': False,
    'enable_ha_router': False,
    'enable_lb': True,
    'enable_firewall': True,
    'enable_vpn': True,
    'enable_fip_topology_check': True,
	...
}
...
TIME_ZONE = "UTC"

3）启动服务

    systemctl restart httpd.service memcached.service

4）浏览器访问

    http://node1_ip/dashboard