Heat Auto scaling
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要使用 Auto scaling ，需要安裝以下 project :
ceilometer
gnocchi
aodh
heat
透過 heat 的 template 來選擇要建立 VM 的各種設定、網路、負載平衡、警告條件等等，以下為 template 的架構圖以及 yaml 範例
yaml 檔案內容:
parameters: 指定 VM 的參數
resources: 定義 db 的規格還有 cloud init 的腳本
asg: 要自動擴展的群組最大最小 VM 數、VM 規格及 cloud init 的腳本
web_server_scale_policy: 設定擴展冷卻時間及一次擴展多少台
cpu_alarm: 設定警告值，granularity 為監測間隔時間，threshold 為警告值
請根據你的環境，修改各參數的ID
heat_template_version: 2016-10-14
description: AutoScaling Wordpress
parameters:
image:
type: string
description: Image used for servers
default: centos
key:
type: string
description: SSH key to connect to the servers
default: test
flavor:
type: string
description: flavor used by the web servers
default: m1.small
database_flavor:
type: string
description: flavor used by the db server
default: m1.small
network:
type: string
description: Network used by the server
default: 8658fdbe-10bb-4d24-b658-6d1b064b0d78
subnet_id:
type: string
description: subnet on which the load balancer will be located
default: 40d8d48c-72be-40c6-9624-bfa5d01120cd
database_name:
type: string
description: Name of the wordpress DB
default: wordpress
database_user:
type: string
description: Name of the wordpress user
default: wordpress
external_network_id:
type: string
description: UUID of a Neutron external network
default: b6fc9587-97b7-4084-a036-3743d475ae4e
resources:
database_password:
type: OS::Heat::RandomString
database_root_password:
type: OS::Heat::RandomString
db:
type: OS::Nova::Server
properties:
flavor: {get_param: database_flavor}
image: {get_param: image}
key_name: {get_param: key}
networks: [{network: {get_param: network} }]
user_data_format: RAW
user_data:
str_replace:
template: |
#!/bin/bash -v
yum install -y epel-release
sudo sed -i "s/metalink=https/metalink=http/" /etc/yum.repos.d/epel.repo
yum -y install mariadb mariadb-server
systemctl enable mariadb.service
systemctl start mariadb.service
mysqladmin -u root password $db_rootpassword
cat << EOF | mysql -u root --password=$db_rootpassword
CREATE DATABASE $db_name;
GRANT ALL PRIVILEGES ON $db_name.* TO "$db_user"@"%"
IDENTIFIED BY "$db_password";
FLUSH PRIVILEGES;
EXIT
EOF
params:
$db_rootpassword: {get_attr: [database_root_password, value]}
$db_name: {get_param: database_name}
$db_user: {get_param: database_user}
$db_password: {get_attr: [database_password, value]}
asg:
type: OS::Heat::AutoScalingGroup
properties:
min_size: 1
max_size: 3
resource:
type: lb_server.yaml
properties:
flavor: {get_param: flavor}
image: {get_param: image}
key_name: {get_param: key}
network: {get_param: network}
subnet: {get_param: subnet_id}
pool_id: {get_resource: pool}
metadata: {"metering.server_group": {get_param: "OS::stack_id"}}
user_data:
str_replace:
template: |
#!/bin/bash -v
yum install -y epel-release
sudo sed -i "s/metalink=https/metalink=http/" /etc/yum.repos.d/epel.repo
yum -y install httpd wordpress
systemctl enable httpd.service
systemctl start httpd.service
setsebool -P httpd_can_network_connect_db=1
sed -i "/Deny from All/d" /etc/httpd/conf.d/wordpress.conf
sed -i "s/Require local/Require all granted/" /etc/httpd/conf.d/wordpress.conf
sed -i s/database_name_here/$db_name/ /etc/wordpress/wp-config.php
sed -i s/username_here/$db_user/ /etc/wordpress/wp-config.php
sed -i s/password_here/$db_password/ /etc/wordpress/wp-config.php
sed -i s/localhost/$db_host/ /etc/wordpress/wp-config.php
systemctl restart httpd.service
params:
$db_name: {get_param: database_name}
$db_user: {get_param: database_user}
$db_password: {get_attr: [database_password, value]}
$db_host: {get_attr: [db, first_address]}
web_server_scaleup_policy:
type: OS::Heat::ScalingPolicy
properties:
adjustment_type: change_in_capacity
auto_scaling_group_id: {get_resource: asg}
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: asg}
cooldown: 60
scaling_adjustment: -1
cpu_alarm_high:
type: OS::Aodh::GnocchiAggregationByResourcesAlarm
properties:
description: Scale up if CPU > 80%
metric: cpu_util
aggregation_method: mean
granularity: 300
evaluation_periods: 1
threshold: 80
resource_type: instance
comparison_operator: gt
alarm_actions:
- str_replace:
template: trust+url
params:
url: {get_attr: [web_server_scaleup_policy, signal_url]}
query:
list_join:
- ''
- - {'=': {server_group: {get_param: "OS::stack_id"}}}
cpu_alarm_low:
type: OS::Aodh::GnocchiAggregationByResourcesAlarm
properties:
description: Scale down if CPU < 15% for 5 minutes
metric: cpu_util
aggregation_method: mean
granularity: 300
evaluation_periods: 1
threshold: 15
resource_type: instance
comparison_operator: lt
alarm_actions:
- str_replace:
template: trust+url
params:
url: {get_attr: [web_server_scaledown_policy, signal_url]}
query:
list_join:
- ''
- - {'=': {server_group: {get_param: "OS::stack_id"}}}
lb:
type: OS::Neutron::LBaaS::LoadBalancer
properties:
vip_subnet: {get_param: subnet_id}
listener:
type: OS::Neutron::LBaaS::Listener
properties:
loadbalancer: {get_resource: lb}
protocol: HTTP
protocol_port: 80
pool:
type: OS::Neutron::LBaaS::Pool
properties:
listener: {get_resource: listener}
lb_algorithm: ROUND_ROBIN
protocol: HTTP
session_persistence:
type: SOURCE_IP
lb_monitor:
type: OS::Neutron::LBaaS::HealthMonitor
properties:
pool: { get_resource: pool }
type: TCP
delay: 5
max_retries: 5
timeout: 5
# assign a floating ip address to the load balancer
# pool.
lb_floating:
type: OS::Neutron::FloatingIP
properties:
floating_network_id: {get_param: external_network_id}
port_id: {get_attr: [lb, 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: [lb, vip_address]}
description: The IP address of the load balancing pool
website_url:
value:
str_replace:
template: http://host/wordpress/
params:
host: { get_attr: [lb_floating, floating_ip_address] }
description: >
This URL is the "external" URL that can be used to access the
Wordpress site.
gnocchi_query:
value:
str_replace:
template: >
gnocchi measures aggregation --resource-type instance
--query 'server_group="stackval"'
--granularity 300 --aggregation mean -m cpu_util
params:
stackval: { get_param: "OS::stack_id" }
description: >
This is a Gnocchi query for statistics on the cpu_util measurements about
OS::Nova::Server instances in this stack. The --resource-type select the
type of Gnocchi resource. The --query parameter filters resources
according to its attributes. When a VM's metadata includes an item of the
form metering.server_group=X, the corresponding Gnocchi resource has a
attribute named server_group that can queried with 'server_group="X"' 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.server_group=X, where X is this stack's ID.heat_template_version: 2016-10-14
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
subnet:
type: string
description: Subnet 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}
user_data_format: RAW
networks: [{network: {get_param: network} }]
member:
type: OS::Neutron::LBaaS::PoolMember
properties:
pool: {get_param: pool_id}
address: {get_attr: [server, first_address]}
protocol_port: 80
subnet: {get_param: subnet}
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] }
建立一個stack (autoscaling.yaml 和 lb_server.yaml 需在同一目錄)
openstack stack create -f yaml -t autoscaling.yaml autoscalingstack 建立完成後，等待 VM 執行完 cloud init 腳本，完成後可由 horizon 的 stack overview 或指令 opesntack stack show STACK_ID 得到 wordpress 網址以及查看此 stack 的 cpu使用率的 gnocchi 指令
使用 gnocchi 指令查看 stack 的 cpu 使用率
# gnocchi measures aggregation --resource-type instance --query 'server_group="60cf8c8b-8d82-432c-b169-b06227396e1a"' --granularity 60 --aggregation mean -m cpu_util
+---------------------------+-------------+----------------+
| timestamp | granularity | value |
+---------------------------+-------------+----------------+
| 2018-05-04T03:12:00+00:00 | 60.0 | 24.4630478097 |
| 2018-05-04T03:13:00+00:00 | 60.0 | 0.308446298992 |
+---------------------------+-------------+----------------+根據 ceilometer 設定的監測間隔，使用 openstack alarm lis t指令來查看 aodh 的警示是否有狀態，如果 state 狀態為 ok 或 alarm，代表 aodh 有得到監測值，如果是 insufficient data，代表兩種可能，一種是 ceilometer 每5分鐘監測一次，但是還沒有5分鐘，因此還在收集資料，另一種是在 heat template 的 cpu_alarm 中granularity 設定錯誤，導致無法取得監測值
# openstack alarm list
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+
| alarm_id | type | name | state | severity | enabled |
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+
| 9a914faa-731e-4dc7-9141-7ed8a0865677 | gnocchi_aggregation_by_resources_threshold | autoscaling-cpu_alarm_high-yuvxqnp37qte | ok | low | True |
| 0f6eef1d-2d15-4193-b1ad-b7bf44a65d3d | gnocchi_aggregation_by_resources_threshold | autoscaling-cpu_alarm_low-ppos7sorcnw3 | alarm | low | True |
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+接下來進入 wordpress 的 vm，安裝 stress，並使用 stress 讓 cpu 到達100%
# yum install -y stress
# stress -c 4再使用 openstack alarm list 查看 cpu_alarm_high 的 state是否為 high，是的話VM 就會自動增加一台，反之減少
# openstack alarm list
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+
| alarm_id | type | name | state | severity | enabled |
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+
| 9a914faa-731e-4dc7-9141-7ed8a0865677 | gnocchi_aggregation_by_resources_threshold | autoscaling-cpu_alarm_high-yuvxqnp37qte | alarm | low | True |
| 0f6eef1d-2d15-4193-b1ad-b7bf44a65d3d | gnocchi_aggregation_by_resources_threshold | autoscaling-cpu_alarm_low-ppos7sorcnw3 | ok | low | True |
+--------------------------------------+--------------------------------------------+-----------------------------------------+-------+----------+---------+此範例取至 OpenStack Heat template ()
