计算的自动扩展

Red Hat OpenStack Platform 8

在 Red Hat OpenStack Platform 中配置自动扩展

OpenStack Documentation Team

rhos-docs@redhat.com

法律通告

摘要

自动缩放您的计算实例，以响应系统使用量。

第 1 章为计算配置自动扩展
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本指南论述了如何根据大量系统使用自动横向扩展您的计算实例。通过使用考虑 CPU 或内存使用情况等因素的预定义规则，您可以将编排(heat)配置为根据需要自动添加和删除其他实例。

1.1. 架构概述
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1.1.1. 编配
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自动扩展后的核心组件是 Orchestration (heat)。编排允许您使用人类可读的 YAML 模板来定义规则。这些规则可在决定添加额外的实例之前评估遥测数据。然后，一旦活动到期，编排可以自动删除任何不需要的实例。

1.1.2. Telemetry
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Telemetry 可以对您的 OpenStack 环境进行性能监控，从而收集实例和物理主机的 CPU、存储和内存使用率。在评估是否执行任何预定义操作时，编配模板会检查遥测数据。

1.1.3. 主要术语
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堆栈 -堆栈包含运行应用程序所需的所有资源。它可以像单个实例及其资源那样简单，或者像多个实例那样复杂，其中包含包含多层应用的所有资源依赖项。
模板 - YAML 脚本，以定义 Heat 要执行的一系列任务。例如，最好将单独的模板用于某些功能：
- 堆栈模板 - 您定义 Telemetry 应该响应的阈值，并且定义自动扩展组。
- 环境模板 - 定义环境的构建信息：要使用的类别和镜像、应如何配置虚拟网络以及如何安装哪些软件。

1.2. 示例：基于 CPU 使用情况自动扩展
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在本例中，编排检查遥测数据，并且自动增加实例的数量，以响应高 CPU 使用量。创建堆栈模板和环境模板，以定义所需的规则和后续配置。本例利用了现有资源（如网络）和使用在您自己的环境中可能不同的名称。

创建环境模板，描述实例类别、网络配置和镜像类型。在 /etc/heat/templates/cirros.yaml 中输入以下值：

heat_template_version: 2014-10-16
description: A base Cirros 0.3.4 server

resources:
  server:
    type: OS::Nova::Server
    properties:
      block_device_mapping:
        - device_name: vda
          delete_on_termination: true
          volume_id: { get_resource: volume }
      flavor: m1.nano
      key_name: admin
      networks:
        - port: { get_resource: port }

  port:
    type: OS::Neutron::Port
    properties:
      network: private
      security_groups:
        - all

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network: public

  floating_ip_assoc:
    type: OS::Neutron::FloatingIPAssociation
    properties:
      floatingip_id: { get_resource: floating_ip }
      port_id: { get_resource: port }

  volume:
    type: OS::Cinder::Volume
    properties:
      image: 'Cirros 0.3.4'
      size: 1

heat_template_version: 2014-10-16
description: A base Cirros 0.3.4 server

resources:
  server:
    type: OS::Nova::Server
    properties:
      block_device_mapping:
        - device_name: vda
          delete_on_termination: true
          volume_id: { get_resource: volume }
      flavor: m1.nano
      key_name: admin
      networks:
        - port: { get_resource: port }

  port:
    type: OS::Neutron::Port
    properties:
      network: private
      security_groups:
        - all

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network: public

  floating_ip_assoc:
    type: OS::Neutron::FloatingIPAssociation
    properties:
      floatingip_id: { get_resource: floating_ip }
      port_id: { get_resource: port }

  volume:
    type: OS::Cinder::Volume
    properties:
      image: 'Cirros 0.3.4'
      size: 1

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在 /root/environment.yaml 中注册 Orchestration 资源：

resource_registry:

    "OS::Nova::Server::Cirros": "file:///etc/heat/templates/cirros.yaml"

resource_registry:

    "OS::Nova::Server::Cirros": "file:///etc/heat/templates/cirros.yaml"

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创建堆栈模板，描述要监视的 CPU 阈值，以及应添加多少个实例。同时也创建实例组，定义可参与此模板的最小和最大实例数量。

在 /root/example.yaml 中输入以下值：

heat_template_version: 2014-10-16
description: Example auto scale group, policy and alarm
resources:
  scaleup_group:
    type: OS::Heat::AutoScalingGroup
    properties:
      cooldown: 60
      desired_capacity: 1
      max_size: 3
      min_size: 1
      resource:
        type: OS::Nova::Server::Cirros

  scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: 1

  scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: -1

  cpu_alarm_high:
    type: OS::Ceilometer::Alarm
    properties:
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 50
      alarm_actions:
        - {get_attr: [scaleup_policy, alarm_url]}
      comparison_operator: gt

  cpu_alarm_low:
    type: OS::Ceilometer::Alarm
    properties:
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 10
      alarm_actions:
        - {get_attr: [scaledown_policy, alarm_url]}
      comparison_operator: lt

heat_template_version: 2014-10-16
description: Example auto scale group, policy and alarm
resources:
  scaleup_group:
    type: OS::Heat::AutoScalingGroup
    properties:
      cooldown: 60
      desired_capacity: 1
      max_size: 3
      min_size: 1
      resource:
        type: OS::Nova::Server::Cirros

  scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: 1

  scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: -1

  cpu_alarm_high:
    type: OS::Ceilometer::Alarm
    properties:
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 50
      alarm_actions:
        - {get_attr: [scaleup_policy, alarm_url]}
      comparison_operator: gt

  cpu_alarm_low:
    type: OS::Ceilometer::Alarm
    properties:
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 10
      alarm_actions:
        - {get_attr: [scaledown_policy, alarm_url]}
      comparison_operator: lt

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更新遥测集合间隔。默认情况下，Telemetry 每 10 分钟轮询实例，以进行 CPU 数据。在本例中，将 /etc/ceilometer/pipeline.yaml 中的间隔更改为 60 秒：
```
- name: cpu_source
interval: 60
meters:
- "cpu"
sinks:
- cpu_sink
```
```
- name: cpu_source
interval: 60
meters:
- "cpu"
sinks:
- cpu_sink
```
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注意
不建议在生产环境中使用 60 秒的轮询周期，因为更高的轮询间隔可能会导致 control plane 的负载增加。
重启所有 OpenStack 服务以应用更新的 Telemetry 设置：
```
openstack-service restart
```
```
# openstack-service restart
```
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注意
此步骤将导致 OpenStack 部署简单中断。

运行编配脚本以构建环境并部署实例：

heat stack-create example -f /root/example.yaml -e /root/environment.yaml
+--------------------------------------+------------+--------------------+----------------------+
| id                                   | stack_name | stack_status       | creation_time        |
+--------------------------------------+------------+--------------------+----------------------+
| 6fca513c-25a1-4849-b7ab-909e37f52eca | example    | CREATE_IN_PROGRESS | 2015-08-31T16:18:02Z |
+--------------------------------------+------------+--------------------+----------------------+

# heat stack-create example -f /root/example.yaml -e /root/environment.yaml
+--------------------------------------+------------+--------------------+----------------------+
| id                                   | stack_name | stack_status       | creation_time        |
+--------------------------------------+------------+--------------------+----------------------+
| 6fca513c-25a1-4849-b7ab-909e37f52eca | example    | CREATE_IN_PROGRESS | 2015-08-31T16:18:02Z |
+--------------------------------------+------------+--------------------+----------------------+

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编配将创建堆栈并启动单个 cirros 实例，如 scaleup_group 定义中设置的： min_size ：

nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

# nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

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编排也创建两个 cpu 警报，它们用于触发扩展或缩减事件，如 cpu_alarm_high 和 cpu_alarm_low 定义：

ceilometer alarm-list
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+
| Alarm ID                             | Name                                | State             | Severity | Enabled | Continuous | Alarm condition                | Time constraints |
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+
| 04b4f845-f5b6-4c5a-8af0-59e03c22e6fa | example-cpu_alarm_high-rd5kysmlahvx | ok                | low      | True    | True       | cpu_util > 50.0 during 1 x 60s | None             |
| ac81cd81-20b3-45f9-bea4-e51f00499602 | example-cpu_alarm_low-6t65kswutupz  | ok                | low      | True    | True       | cpu_util < 10.0 during 1 x 60s | None             |
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+

# ceilometer alarm-list
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+
| Alarm ID                             | Name                                | State             | Severity | Enabled | Continuous | Alarm condition                | Time constraints |
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+
| 04b4f845-f5b6-4c5a-8af0-59e03c22e6fa | example-cpu_alarm_high-rd5kysmlahvx | ok                | low      | True    | True       | cpu_util > 50.0 during 1 x 60s | None             |
| ac81cd81-20b3-45f9-bea4-e51f00499602 | example-cpu_alarm_low-6t65kswutupz  | ok                | low      | True    | True       | cpu_util < 10.0 during 1 x 60s | None             |
+--------------------------------------+-------------------------------------+-------------------+----------+---------+------------+--------------------------------+------------------+

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1.2.1. 测试自动扩展实例
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编配根据 cpu_alarm_high 阈值自动扩展实例。CPU 使用率超过 50% 实例将扩展，如 cpu_alarm_high 定义中的设置： threshold: 50
要生成 CPU 负载，请登录实例并运行 dd 命令：

ssh -i admin.pem cirros@192.168.122.232
dd if=/dev/zero of=/dev/null &
dd if=/dev/zero of=/dev/null &
dd if=/dev/zero of=/dev/null &

$ ssh -i admin.pem cirros@192.168.122.232
$ dd if=/dev/zero of=/dev/null &
$ dd if=/dev/zero of=/dev/null &
$ dd if=/dev/zero of=/dev/null &

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运行 dd 命令后，您可以预期在 cirros 实例中具有 100% 的 CPU 使用率。在 60 秒后，您应该看到编排已将组自动扩展到两个实例：

nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
| 0f69dfbe-4654-474f-9308-1b64de3f5c18 | ex-qeki-qmvor5rkptj7-krq7i66h6n7b-server-b4pk3dzjvbpi | ACTIVE | -          | Running     | private=10.10.1.157, 192.168.122.235 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

# nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
| 0f69dfbe-4654-474f-9308-1b64de3f5c18 | ex-qeki-qmvor5rkptj7-krq7i66h6n7b-server-b4pk3dzjvbpi | ACTIVE | -          | Running     | private=10.10.1.157, 192.168.122.235 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

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进一步的 60 秒后，您将观察编排已再次自动扩展到三个实例。由于三个是此配置的最大值，因此它不会扩展任何更高的值（如 scaleup_group 定义中设置的一样： max_size）

nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
| 0e805e75-aa6f-4375-b057-2c173b68f172 | ex-qeki-gajdwmu2cgm2-vckf4g2gpwis-server-r3smbhtqij76 | ACTIVE | -          | Running     | private=10.10.1.158, 192.168.122.236 |
| 0f69dfbe-4654-474f-9308-1b64de3f5c18 | ex-qeki-qmvor5rkptj7-krq7i66h6n7b-server-b4pk3dzjvbpi | ACTIVE | -          | Running     | private=10.10.1.157, 192.168.122.235 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

# nova list
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| ID                                   | Name                                                  | Status | Task State | Power State | Networks                             |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+
| 3f627c84-06aa-4782-8c12-29409964cc73 | ex-qeki-3azno6me5gvm-pqmr5zd6kuhm-server-gieck7uoyrwc | ACTIVE | -          | Running     | private=10.10.1.156, 192.168.122.234 |
| 0e805e75-aa6f-4375-b057-2c173b68f172 | ex-qeki-gajdwmu2cgm2-vckf4g2gpwis-server-r3smbhtqij76 | ACTIVE | -          | Running     | private=10.10.1.158, 192.168.122.236 |
| 0f69dfbe-4654-474f-9308-1b64de3f5c18 | ex-qeki-qmvor5rkptj7-krq7i66h6n7b-server-b4pk3dzjvbpi | ACTIVE | -          | Running     | private=10.10.1.157, 192.168.122.235 |
+--------------------------------------+-------------------------------------------------------+--------+------------+-------------+--------------------------------------+

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1.2.2. 自动缩放实例
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编排根据 cpu_alarm_low 阈值自动扩展实例。在本例中，当 CPU 使用率低于 10% 后，实例将缩减。终止正在运行的 dd 进程，您将观察编排开始缩减实例。

停止 dd 进程会导致 cpu_alarm_low 事件触发。因此，编配过程开始自动扩展并删除实例：

ceilometer alarm-list
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+
| Alarm ID                             | Name                                | State | Severity | Enabled | Continuous | Alarm condition                | Time constraints |
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+
| 04b4f845-f5b6-4c5a-8af0-59e03c22e6fa | example-cpu_alarm_high-rd5kysmlahvx | ok    | low      | True    | True       | cpu_util > 50.0 during 1 x 60s | None             |
| ac81cd81-20b3-45f9-bea4-e51f00499602 | example-cpu_alarm_low-6t65kswutupz  | alarm | low      | True    | True       | cpu_util < 10.0 during 1 x 60s | None             |
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+

# ceilometer alarm-list
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+
| Alarm ID                             | Name                                | State | Severity | Enabled | Continuous | Alarm condition                | Time constraints |
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+
| 04b4f845-f5b6-4c5a-8af0-59e03c22e6fa | example-cpu_alarm_high-rd5kysmlahvx | ok    | low      | True    | True       | cpu_util > 50.0 during 1 x 60s | None             |
| ac81cd81-20b3-45f9-bea4-e51f00499602 | example-cpu_alarm_low-6t65kswutupz  | alarm | low      | True    | True       | cpu_util < 10.0 during 1 x 60s | None             |
+--------------------------------------+-------------------------------------+-------+----------+---------+------------+--------------------------------+------------------+

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几分钟后，您可以返回到单个实例，在 scaleup_group 中允许的最小实例数量：min_size: 1

1.3. 示例：自动扩展应用程序
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之前描述的功能也可用于扩展应用程序；例如，一种由一次运行的多个实例提供的动态网页。在这种情况下，可以配置 neutron 来提供 负载平衡即服务， 从而在实例之间平均分配流量。

在以下示例中，编排会再次检查遥测数据，并在检测到高 CPU 使用量时增加实例数量，或者在 CPU 使用量低于集合值时减少实例数量。

创建描述 负载均衡器 环境属性的模板。在 /etc/heat/templates/lb-env.yaml 中输入以下值：

heat_template_version: 2014-10-16
description: A load-balancer server
parameters:
  image:
    type: string
    description: Image used for servers
  key_name:
    type: string
    description: SSH key to connect to the servers
  flavor:
    type: string
    description: flavor used by the servers
  pool_id:
    type: string
    description: Pool to contact
  user_data:
    type: string
    description: Server user_data
  metadata:
    type: json
  network:
    type: string
    description: Network used by the server

resources:
  server:
    type: OS::Nova::Server
    properties:
      flavor: {get_param: flavor}
      image: {get_param: image}
      key_name: {get_param: key_name}
      metadata: {get_param: metadata}
      user_data: {get_param: user_data}
      networks:
        - port: { get_resource: port }

  member:
    type: OS::Neutron::PoolMember
    properties:
      pool_id: {get_param: pool_id}
      address: {get_attr: [server, first_address]}
      protocol_port: 80

  port:
    type: OS::Neutron::Port
    properties:
      network: {get_param: network}
      security_groups:
        - base

outputs:
  server_ip:
    description: IP Address of the load-balanced server.
    value: { get_attr: [server, first_address] }
  lb_member:
    description: LB member details.
    value: { get_attr: [member, show] }

heat_template_version: 2014-10-16
description: A load-balancer server
parameters:
  image:
    type: string
    description: Image used for servers
  key_name:
    type: string
    description: SSH key to connect to the servers
  flavor:
    type: string
    description: flavor used by the servers
  pool_id:
    type: string
    description: Pool to contact
  user_data:
    type: string
    description: Server user_data
  metadata:
    type: json
  network:
    type: string
    description: Network used by the server

resources:
  server:
    type: OS::Nova::Server
    properties:
      flavor: {get_param: flavor}
      image: {get_param: image}
      key_name: {get_param: key_name}
      metadata: {get_param: metadata}
      user_data: {get_param: user_data}
      networks:
        - port: { get_resource: port }

  member:
    type: OS::Neutron::PoolMember
    properties:
      pool_id: {get_param: pool_id}
      address: {get_attr: [server, first_address]}
      protocol_port: 80

  port:
    type: OS::Neutron::Port
    properties:
      network: {get_param: network}
      security_groups:
        - base

outputs:
  server_ip:
    description: IP Address of the load-balanced server.
    value: { get_attr: [server, first_address] }
  lb_member:
    description: LB member details.
    value: { get_attr: [member, show] }

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为要运行 Web 应用的实例创建另一个模板。以下模板会创建一个负载均衡器并使用现有的网络。确保根据您的环境替换参数，并将模板保存到文件中，如 /root/lb-webserver-rhel7.yaml ：

heat_template_version: 2014-10-16
description: AutoScaling RHEL 7 Web Application
parameters:
  image:
    type: string
    description: Image used for servers
    default: RHEL 7
  key_name:
    type: string
    description: SSH key to connect to the servers
    default: admin
  flavor:
    type: string
    description: flavor used by the web servers
    default: m2.tiny
  network:
    type: string
    description: Network used by the server
    default: private
  subnet_id:
    type: string
    description: subnet on which the load balancer will be located
    default: 9daa6b7d-e647-482a-b387-dd5f855b88ef
  external_network_id:
    type: string
    description: UUID of a Neutron external network
    default: db17c885-77fa-45e8-8647-dbb132517960

resources:
  webserver:
    type: OS::Heat::AutoScalingGroup
    properties:
      min_size: 1
      max_size: 3
      cooldown: 60
      desired_capacity: 1
      resource:
        type: file:///etc/heat/templates/lb-env.yaml
        properties:
          flavor: {get_param: flavor}
          image: {get_param: image}
          key_name: {get_param: key_name}
          network: {get_param: network}
          pool_id: {get_resource: pool}
          metadata: {"metering.stack": {get_param: "OS::stack_id"}}
          user_data:
            str_replace:
              template: |
                #!/bin/bash -v

                yum -y install httpd php
                systemctl enable httpd
                systemctl start httpd
                cat <<EOF > /var/www/html/hostname.php
                <?php echo "Hello, My name is " . php_uname('n'); ?>
                EOF
              params:
                hostip: 192.168.122.70
                fqdn: sat6.example.com
                shortname: sat6

  web_server_scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: {get_resource: webserver}
      cooldown: 60
      scaling_adjustment: 1

  web_server_scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: {get_resource: webserver}
      cooldown: 60
      scaling_adjustment: -1

  cpu_alarm_high:
    type: OS::Ceilometer::Alarm
    properties:
      description: Scale-up if the average CPU > 95% for 1 minute
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 95
      alarm_actions:
        - {get_attr: [web_server_scaleup_policy, alarm_url]}
      matching_metadata: {'metadata.user_metadata.stack': {get_param: "OS::stack_id"}}
      comparison_operator: gt

  cpu_alarm_low:
    type: OS::Ceilometer::Alarm
    properties:
      description: Scale-down if the average CPU < 15% for 1 minute
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 15
      alarm_actions:
        - {get_attr: [web_server_scaledown_policy, alarm_url]}
      matching_metadata: {'metadata.user_metadata.stack': {get_param: "OS::stack_id"}}
      comparison_operator: lt

  monitor:
    type: OS::Neutron::HealthMonitor
    properties:
      type: TCP
      delay: 5
      max_retries: 5
      timeout: 5

  pool:
    type: OS::Neutron::Pool
    properties:
      protocol: HTTP
      monitors: [{get_resource: monitor}]
      subnet_id: {get_param: subnet_id}
      lb_method: ROUND_ROBIN
      vip:
        protocol_port: 80

  lb:
    type: OS::Neutron::LoadBalancer
    properties:
      protocol_port: 80
      pool_id: {get_resource: pool}

  lb_floating:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: {get_param: external_network_id}
      port_id: {get_attr: [pool, vip, port_id]}

outputs:
  scale_up_url:
    description: >
      This URL is the webhook to scale up the autoscaling group.  You
      can invoke the scale-up operation by doing an HTTP POST to this
      URL; no body nor extra headers are needed.
    value: {get_attr: [web_server_scaleup_policy, alarm_url]}
  scale_dn_url:
    description: >
      This URL is the webhook to scale down the autoscaling group.
      You can invoke the scale-down operation by doing an HTTP POST to
      this URL; no body nor extra headers are needed.
    value: {get_attr: [web_server_scaledown_policy, alarm_url]}
  pool_ip_address:
    value: {get_attr: [pool, vip, address]}
    description: The IP address of the load balancing pool
  website_url:
    value:
      str_replace:
        template: http://serviceip/hostname.php
        params:
          serviceip: { get_attr: [lb_floating, floating_ip_address] }
    description: >
      This URL is the "external" URL that can be used to access the
      website.
  ceilometer_query:
    value:
      str_replace:
        template: >
          ceilometer statistics -m cpu_util
          -q metadata.user_metadata.stack=stackval -p 60 -a avg
        params:
          stackval: { get_param: "OS::stack_id" }
    description: >
      This is a Ceilometer query for statistics on the cpu_util meter
      Samples about OS::Nova::Server instances in this stack.  The -q
      parameter selects Samples according to the subject's metadata.
      When a VM's metadata includes an item of the form metering.X=Y,
      the corresponding Ceilometer resource has a metadata item of the
      form user_metadata.X=Y and samples about resources so tagged can
      be queried with a Ceilometer query term of the form
      metadata.user_metadata.X=Y.  In this case the nested stacks give
      their VMs metadata that is passed as a nested stack parameter,
      and this stack passes a metadata of the form metering.stack=Y,
      where Y is this stack's ID.

heat_template_version: 2014-10-16
description: AutoScaling RHEL 7 Web Application
parameters:
  image:
    type: string
    description: Image used for servers
    default: RHEL 7
  key_name:
    type: string
    description: SSH key to connect to the servers
    default: admin
  flavor:
    type: string
    description: flavor used by the web servers
    default: m2.tiny
  network:
    type: string
    description: Network used by the server
    default: private
  subnet_id:
    type: string
    description: subnet on which the load balancer will be located
    default: 9daa6b7d-e647-482a-b387-dd5f855b88ef
  external_network_id:
    type: string
    description: UUID of a Neutron external network
    default: db17c885-77fa-45e8-8647-dbb132517960

resources:
  webserver:
    type: OS::Heat::AutoScalingGroup
    properties:
      min_size: 1
      max_size: 3
      cooldown: 60
      desired_capacity: 1
      resource:
        type: file:///etc/heat/templates/lb-env.yaml
        properties:
          flavor: {get_param: flavor}
          image: {get_param: image}
          key_name: {get_param: key_name}
          network: {get_param: network}
          pool_id: {get_resource: pool}
          metadata: {"metering.stack": {get_param: "OS::stack_id"}}
          user_data:
            str_replace:
              template: |
                #!/bin/bash -v

                yum -y install httpd php
                systemctl enable httpd
                systemctl start httpd
                cat <<EOF > /var/www/html/hostname.php
                <?php echo "Hello, My name is " . php_uname('n'); ?>
                EOF
              params:
                hostip: 192.168.122.70
                fqdn: sat6.example.com
                shortname: sat6

  web_server_scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: {get_resource: webserver}
      cooldown: 60
      scaling_adjustment: 1

  web_server_scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: {get_resource: webserver}
      cooldown: 60
      scaling_adjustment: -1

  cpu_alarm_high:
    type: OS::Ceilometer::Alarm
    properties:
      description: Scale-up if the average CPU > 95% for 1 minute
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 95
      alarm_actions:
        - {get_attr: [web_server_scaleup_policy, alarm_url]}
      matching_metadata: {'metadata.user_metadata.stack': {get_param: "OS::stack_id"}}
      comparison_operator: gt

  cpu_alarm_low:
    type: OS::Ceilometer::Alarm
    properties:
      description: Scale-down if the average CPU < 15% for 1 minute
      meter_name: cpu_util
      statistic: avg
      period: 60
      evaluation_periods: 1
      threshold: 15
      alarm_actions:
        - {get_attr: [web_server_scaledown_policy, alarm_url]}
      matching_metadata: {'metadata.user_metadata.stack': {get_param: "OS::stack_id"}}
      comparison_operator: lt

  monitor:
    type: OS::Neutron::HealthMonitor
    properties:
      type: TCP
      delay: 5
      max_retries: 5
      timeout: 5

  pool:
    type: OS::Neutron::Pool
    properties:
      protocol: HTTP
      monitors: [{get_resource: monitor}]
      subnet_id: {get_param: subnet_id}
      lb_method: ROUND_ROBIN
      vip:
        protocol_port: 80

  lb:
    type: OS::Neutron::LoadBalancer
    properties:
      protocol_port: 80
      pool_id: {get_resource: pool}

  lb_floating:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network_id: {get_param: external_network_id}
      port_id: {get_attr: [pool, vip, port_id]}

outputs:
  scale_up_url:
    description: >
      This URL is the webhook to scale up the autoscaling group.  You
      can invoke the scale-up operation by doing an HTTP POST to this
      URL; no body nor extra headers are needed.
    value: {get_attr: [web_server_scaleup_policy, alarm_url]}
  scale_dn_url:
    description: >
      This URL is the webhook to scale down the autoscaling group.
      You can invoke the scale-down operation by doing an HTTP POST to
      this URL; no body nor extra headers are needed.
    value: {get_attr: [web_server_scaledown_policy, alarm_url]}
  pool_ip_address:
    value: {get_attr: [pool, vip, address]}
    description: The IP address of the load balancing pool
  website_url:
    value:
      str_replace:
        template: http://serviceip/hostname.php
        params:
          serviceip: { get_attr: [lb_floating, floating_ip_address] }
    description: >
      This URL is the "external" URL that can be used to access the
      website.
  ceilometer_query:
    value:
      str_replace:
        template: >
          ceilometer statistics -m cpu_util
          -q metadata.user_metadata.stack=stackval -p 60 -a avg
        params:
          stackval: { get_param: "OS::stack_id" }
    description: >
      This is a Ceilometer query for statistics on the cpu_util meter
      Samples about OS::Nova::Server instances in this stack.  The -q
      parameter selects Samples according to the subject's metadata.
      When a VM's metadata includes an item of the form metering.X=Y,
      the corresponding Ceilometer resource has a metadata item of the
      form user_metadata.X=Y and samples about resources so tagged can
      be queried with a Ceilometer query term of the form
      metadata.user_metadata.X=Y.  In this case the nested stacks give
      their VMs metadata that is passed as a nested stack parameter,
      and this stack passes a metadata of the form metering.stack=Y,
      where Y is this stack's ID.

Copy to Clipboard

Toggle word wrap

更新遥测集合间隔。默认情况下，Telemetry 每 10 分钟轮询实例，以进行 CPU 数据。在本例中，将 /etc/ceilometer/pipeline.yaml 中的间隔更改为 60 秒：
```
- name: cpu_source
interval: 60
meters:
- "cpu"
sinks:
- cpu_sink
```
```
- name: cpu_source
interval: 60
meters:
- "cpu"
sinks:
- cpu_sink
```
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注意
不建议在生产环境中使用 60 秒的轮询周期，因为更高的轮询间隔可能会导致 control plane 的负载增加。
重启所有 OpenStack 服务以应用更新的 Telemetry 设置：
```
openstack-service restart
```
```
# openstack-service restart
```
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注意
此步骤将导致 OpenStack 部署简单中断。
运行编配脚本。这将构建环境，并使用模板来部署实例：
```
heat stack-create webfarm -f /root/lb-webserver-rhel7.yaml
```
```
# heat stack-create webfarm -f /root/lb-webserver-rhel7.yaml
```
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将 /root/lb-webserver-rhel7.yaml 替换为实际路径和文件名。

您可以在 Dashboard 的 Orchestration → Stacks → Webfarm 下监控堆栈的创建。创建堆栈后，您会看到多个有用的信息，特别是：

用于触发手动扩展或缩减事件的 URL。
浮动 IP 地址，即网站的 IP 地址。
Telemetry 命令显示整个堆栈的 CPU 负载，您可以使用它来检查扩展是否按预期工作。

这是页面在 Dashboard 中是什么样子：

heat stack output

打开 Network → Load Balancers 来查看负载均衡器：

load balancer

单击 Members。此页面显示负载平衡池的成员；它们是网站流量可以分发到的实例。请注意，在创建了对应的实例并且安装和配置了 Apache 之前，成员将没有 Active 状态。

当 web 服务器启动时，实例将显示为负载均衡器的活动成员：

load balancer member active

现在，您可以通过 http://IP/hostname.php 访问 Web 应用。您可以看到类似如下的输出：

Hello, My name is we-zrwm-t4ezkpx34gxu-qbg5d7dqbc4j-server-mzdvigk2jugl

Hello, My name is we-zrwm-t4ezkpx34gxu-qbg5d7dqbc4j-server-mzdvigk2jugl

Copy to Clipboard

Toggle word wrap

现在，您可以通过从仪表板中的堆栈概述运行 Telemetry 命令来查看堆栈的 CPU 性能数据。该命令类似如下：

ceilometer statistics -m cpu_util -q metadata.user_metadata.stack=8f86c3d5-15cf-4a64-b9e8-70215498c046 -p 60 -a avg

# ceilometer statistics -m cpu_util -q metadata.user_metadata.stack=8f86c3d5-15cf-4a64-b9e8-70215498c046 -p 60 -a avg

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Toggle word wrap

1.3.1. 测试自动扩展应用程序
复制链接

要手动触发应用程序扩展，请在 仪表板中使用来自堆栈概述的 REST 扩展 URL，或者通过在初始部署实例上运行资源密集型命令来生成负载。

要使用 REST API，您需要一个能够执行 HTTP POST 请求的工具，如 REST Easy Firefox add on 或 curl。复制 扩展 URL，并将其粘贴到 REST Easy 表单中：

或者将其用作 curl 命令行中的参数：
```
curl -X POST "scale-up URL"
```
```
$ curl -X POST "scale-up URL"
```
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为人为生成负载，请为实例分配一个浮动 IP，使用 SSH 登录该实例，再运行命令，使 CPU 处于忙碌状态。例如：
```
dd if=/dev/zero of=/dev/null &
```
```
$ dd if=/dev/zero of=/dev/null &
```
Copy to Clipboard Toggle word wrap
重要
检查 CPU 用量是否超过 95%，例如使用 top 命令。如果 CPU 使用率不够高，请多次并行运行 dd 命令，或使用其它方法保持 CPU 忙碌。

下一次 Telemetry 从堆栈收集 CPU 数据时，扩展事件将在 Orchestration → Stacks → Webfarm → Events 触发并出现。将创建一个新的 Web 服务器实例，并添加到负载平衡器中。完成此操作后，实例就会变为活动状态，您会注意到网站 URL 通过负载均衡器路由到堆栈中的两个实例。

注意

创建可能需要几分钟时间，因为实例必须初始化、安装和配置 Apache，以及部署的应用程序。这由 HAProxy 监控，确保在实例上可用该网站标记为 active。

这是在创建新实例时，负载均衡池的成员列表是什么样子：

scale up load balancer

重要

在决定是否创建额外的实例被创建时，将考虑 heat 堆栈中的实例的平均 CPU 使用量。由于第二个实例很可能具有正常的 CPU 使用量，因此它将平衡第一个实例。但是，如果第二个实例变得忙碌，并且第一个实例的平均 CPU 使用量超过 95%，则将创建另一个(third)实例。

1.3.2. 自动缩放故障应用程序
复制链接

这与第 1.2.2 节 “自动缩放实例” 类似，当堆栈的平均 CPU 使用量低于预定义的值时，会触发 scale-down 策略，在第 1.3.1 节 “测试自动扩展应用程序” 中描述的示例中为 15%。另外，通过这种方式从堆栈中删除实例时，也会从负载平衡器中自动移除它。然后，网站流量会在实例的其余部分中自动分发。

法律通告
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计算的自动扩展

在 Red Hat OpenStack Platform 中配置自动扩展

OpenStack Documentation Team

第 1 章为计算配置自动扩展
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1.1. 架构概述
复制链接

1.1.1. 编配
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1.1.2. Telemetry
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1.1.3. 主要术语
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1.2. 示例：基于 CPU 使用情况自动扩展
复制链接

1.2.1. 测试自动扩展实例
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1.2.2. 自动缩放实例
复制链接

1.3. 示例：自动扩展应用程序
复制链接

1.3.1. 测试自动扩展应用程序
复制链接

1.3.2. 自动缩放故障应用程序
复制链接

法律通告
复制链接

学习

尝试、购买和销售

社区

关于红帽文档

让开源更具包容性

關於紅帽

Theme

Red Hat legal and privacy links

Red Hat legal and privacy links

计算的自动扩展

在 Red Hat OpenStack Platform 中配置自动扩展

OpenStack Documentation Team

第 1 章 为计算配置自动扩展复制链接链接已复制到粘贴板!

1.1. 架构概述复制链接链接已复制到粘贴板!

1.1.1. 编配复制链接链接已复制到粘贴板!

1.1.2. Telemetry复制链接链接已复制到粘贴板!

1.1.3. 主要术语复制链接链接已复制到粘贴板!

1.2. 示例：基于 CPU 使用情况自动扩展复制链接链接已复制到粘贴板!

1.2.1. 测试自动扩展实例复制链接链接已复制到粘贴板!

1.2.2. 自动缩放实例复制链接链接已复制到粘贴板!

1.3. 示例：自动扩展应用程序复制链接链接已复制到粘贴板!

1.3.1. 测试自动扩展应用程序复制链接链接已复制到粘贴板!

1.3.2. 自动缩放故障应用程序复制链接链接已复制到粘贴板!

法律通告复制链接链接已复制到粘贴板!

学习

尝试、购买和销售

社区

关于红帽文档

让开源更具包容性

關於紅帽

Theme

Red Hat legal and privacy links

Red Hat legal and privacy links

第 1 章为计算配置自动扩展
复制链接

1.1. 架构概述
复制链接

1.1.1. 编配
复制链接

1.1.2. Telemetry
复制链接

1.1.3. 主要术语
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1.2. 示例：基于 CPU 使用情况自动扩展
复制链接

1.2.1. 测试自动扩展实例
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1.2.2. 自动缩放实例
复制链接

1.3. 示例：自动扩展应用程序
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1.3.1. 测试自动扩展应用程序
复制链接

1.3.2. 自动缩放故障应用程序
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法律通告
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