1717 Configuring AutoScale without using NetScaler
1818=============================================
1919
20- .. warning ::
21- This feature is currently only available on the master branch and will be
20+ .. warning ::
21+ This feature is currently only available on the master branch and will be
2222 released in the 4.4 release.
2323
24+ .. note ::
25+ AutoScaling is currently not supported in the new UI.
26+ To manage AutoScaling, please directly invoke the
27+ respective APIs or use `cloudmonkey <https://github.com/apache/cloudstack-cloudmonkey >`_,
28+ the CLI tool for cloudstack
2429
2530What is AutoScaling?
2631--------------------
2732
28- AutoScaling allows you to scale your back-end services or application VMs up
29- or down seamlessly and automatically according to the conditions you define.
30- With AutoScaling enabled, you can ensure that the number of VMs you are using
31- seamlessly scale up when demand increases, and automatically decreases when
32- demand subsides. Thus it helps you save compute costs by terminating underused
33- VMs automatically and launching new VMs when you need them, without the need
33+ AutoScaling allows you to scale your back-end services or application VMs up
34+ or down seamlessly and automatically according to the conditions you define.
35+ With AutoScaling enabled, you can ensure that the number of VMs you are using
36+ seamlessly scale up when demand increases, and automatically decreases when
37+ demand subsides. Thus it helps you save compute costs by terminating underused
38+ VMs automatically and launching new VMs when you need them, without the need
3439for manual intervention.
3540
3641
3742Hypervisor support
3843------------------
3944
40- At that time, AutoScaling without NetScaler only supports for Xenserver. We
45+ At that time, AutoScaling without NetScaler only supports for Xenserver. We
4146are working to support KVM also.
4247
4348
@@ -46,10 +51,10 @@ Prerequisites
4651
4752Before you configure an AutoScale rule, consider the following:
4853
49- - Ensure that the necessary template is prepared before configuring AutoScale.
50- Firstly you must install the PV-driver, which helps Xenserver collect
51- performance parameters (CPU and memory) into VMs. Beside, When a VM is
52- deployed by using a template and when it comes up, the application should be
54+ - Ensure that the necessary template is prepared before configuring AutoScale.
55+ Firstly you must install the PV-driver, which helps Xenserver collect
56+ performance parameters (CPU and memory) into VMs. Beside, When a VM is
57+ deployed by using a template and when it comes up, the application should be
5358 up and running.
5459
5560
@@ -60,77 +65,77 @@ Specify the following:
6065
6166.. image :: /_static/images/autoscale-config.png
6267
63- - Template: A template consists of a base OS image and application. A
64- template is used to provision the new instance of an application on a
65- scaleup action. When a VM is deployed from a template, the VM can start
66- taking the traffic from the load balancer without any admin intervention.
67- For example, if the VM is deployed for a Web service, it should have the
68+ - Template: A template consists of a base OS image and application. A
69+ template is used to provision the new instance of an application on a
70+ scaleup action. When a VM is deployed from a template, the VM can start
71+ taking the traffic from the load balancer without any admin intervention.
72+ For example, if the VM is deployed for a Web service, it should have the
6873 Web server running, the database connected, and so on.
6974
70- - Compute offering: A predefined set of virtual hardware attributes,
71- including CPU speed, number of CPUs, and RAM size, that the user can select
72- when creating a new virtual machine instance. Choose one of the compute
73- offerings to be used while provisioning a VM instance as part of scaleup
75+ - Compute offering: A predefined set of virtual hardware attributes,
76+ including CPU speed, number of CPUs, and RAM size, that the user can select
77+ when creating a new virtual machine instance. Choose one of the compute
78+ offerings to be used while provisioning a VM instance as part of scaleup
7479 action.
7580
76- - Min Instance: The minimum number of active VM instances that is assigned to
77- a load balancing rule. The active VM instances are the application
78- instances that are up and serving the traffic, and are being load balanced.
79- This parameter ensures that a load balancing rule has at least the
81+ - Min Instance: The minimum number of active VM instances that is assigned to
82+ a load balancing rule. The active VM instances are the application
83+ instances that are up and serving the traffic, and are being load balanced.
84+ This parameter ensures that a load balancing rule has at least the
8085 configured number of active VM instances are available to serve the traffic.
8186
82- - Max Instance: Maximum number of active VM instances that should be assigned
83- to a load balancing rule. This parameter defines the upper limit of active
87+ - Max Instance: Maximum number of active VM instances that should be assigned
88+ to a load balancing rule. This parameter defines the upper limit of active
8489 VM instances that can be assigned to a load balancing rule.
8590
86- Specifying a large value for the maximum instance parameter might result in
87- provisioning large number of VM instances, which in turn leads to a single
88- load balancing rule exhausting the VM instances limit specified at the
91+ Specifying a large value for the maximum instance parameter might result in
92+ provisioning large number of VM instances, which in turn leads to a single
93+ load balancing rule exhausting the VM instances limit specified at the
8994 account or domain level.
9095
9196Specify the following scale-up and scale-down policies:
9297
93- - Duration: The duration, in seconds, for which the conditions you specify
94- must be true to trigger a scaleup action. The conditions defined should
95- hold true for the entire duration you specify for an AutoScale action to be
98+ - Duration: The duration, in seconds, for which the conditions you specify
99+ must be true to trigger a scaleup action. The conditions defined should
100+ hold true for the entire duration you specify for an AutoScale action to be
96101 invoked.
97102
98- - Counter: The performance counters expose the state of the monitored
103+ - Counter: The performance counters expose the state of the monitored
99104 instances. We added two new counter to work with that feature:
100105
101106 - Linux User CPU [native] - percentage
102107 - Linux User RAM [native] - percentage
103108
104- Remember to choose one of them. If you choose anything else, the
109+ Remember to choose one of them. If you choose anything else, the
105110 autoscaling will not work.
106111
107- - Operator: The following five relational operators are supported in
108- AutoScale feature: Greater than, Less than, Less than or equal to, Greater
112+ - Operator: The following five relational operators are supported in
113+ AutoScale feature: Greater than, Less than, Less than or equal to, Greater
109114 than or equal to, and Equal to.
110115
111- - Threshold: Threshold value to be used for the counter. Once the counter
112- defined above breaches the threshold value, the AutoScale feature initiates
116+ - Threshold: Threshold value to be used for the counter. Once the counter
117+ defined above breaches the threshold value, the AutoScale feature initiates
113118 a scaleup or scaledown action.
114119
115120- Add: Click Add to add the condition.
116121
117- Additionally, if you want to configure the advanced settings, click Show
122+ Additionally, if you want to configure the advanced settings, click Show
118123 advanced settings, and specify the following:
119124
120- - Polling interval: Frequency in which the conditions, combination of counter,
121- operator and threshold, are to be evaluated before taking a scale up or
125+ - Polling interval: Frequency in which the conditions, combination of counter,
126+ operator and threshold, are to be evaluated before taking a scale up or
122127 down action. The default polling interval is 30 seconds.
123128
124- - Quiet Time: This is the cool down period after an AutoScale action is
125- initiated. The time includes the time taken to complete provisioning a VM
126- instance from its template and the time taken by an application to be ready
127- to serve traffic. This quiet time allows the fleet to come up to a stable
129+ - Quiet Time: This is the cool down period after an AutoScale action is
130+ initiated. The time includes the time taken to complete provisioning a VM
131+ instance from its template and the time taken by an application to be ready
132+ to serve traffic. This quiet time allows the fleet to come up to a stable
128133 state before any action can take place. The default is 300 seconds.
129134
130- - Destroy VM Grace Period: The duration in seconds, after a scaledown action
131- is initiated, to wait before the VM is destroyed as part of scaledown
132- action. This is to ensure graceful close of any pending sessions or
133- transactions being served by the VM marked for destroy. The default is 120
135+ - Destroy VM Grace Period: The duration in seconds, after a scaledown action
136+ is initiated, to wait before the VM is destroyed as part of scaledown
137+ action. This is to ensure graceful close of any pending sessions or
138+ transactions being served by the VM marked for destroy. The default is 120
134139 seconds.
135140
136141- Apply: Click Apply to create the AutoScale configuration.
@@ -139,39 +144,39 @@ Specify the following scale-up and scale-down policies:
139144Disabling and Enabling an AutoScale Configuration
140145-------------------------------------------------
141146
142- If you want to perform any maintenance operation on the AutoScale VM instances,
143- disable the AutoScale configuration. When the AutoScale configuration is
144- disabled, no scaleup or scaledown action is performed. You can use this
145- downtime for the maintenance activities. To disable the AutoScale
147+ If you want to perform any maintenance operation on the AutoScale VM instances,
148+ disable the AutoScale configuration. When the AutoScale configuration is
149+ disabled, no scaleup or scaledown action is performed. You can use this
150+ downtime for the maintenance activities. To disable the AutoScale
146151configuration, click the Disable AutoScale button.
147152
148- The button toggles between enable and disable, depending on whether AutoScale
149- is currently enabled or not. After the maintenance operations are done, you
150- can enable the AutoScale configuration back. To enable, open the AutoScale
153+ The button toggles between enable and disable, depending on whether AutoScale
154+ is currently enabled or not. After the maintenance operations are done, you
155+ can enable the AutoScale configuration back. To enable, open the AutoScale
151156configuration page again, then click the Enable AutoScale button.
152157
153158
154159Updating an AutoScale Configuration
155160-----------------------------------
156161
157- You can update the various parameters and add or delete the conditions in a
158- scaleup or scaledown rule. Before you update an AutoScale configuration,
159- ensure that you disable the AutoScale load balancer rule by clicking the
162+ You can update the various parameters and add or delete the conditions in a
163+ scaleup or scaledown rule. Before you update an AutoScale configuration,
164+ ensure that you disable the AutoScale load balancer rule by clicking the
160165Disable AutoScale button.
161166
162- After you modify the required AutoScale parameters, click Apply. To apply the
163- new AutoScale policies, open the AutoScale configuration page again, then
167+ After you modify the required AutoScale parameters, click Apply. To apply the
168+ new AutoScale policies, open the AutoScale configuration page again, then
164169click the Enable AutoScale button.
165170
166171
167172Runtime Considerations
168173----------------------
169174
170- An administrator should not assign a VM to a load balancing rule which is
175+ An administrator should not assign a VM to a load balancing rule which is
171176configured for AutoScale.
172177
173- Making API calls outside the context of AutoScale, such as destroyVM, on an
174- autoscaled VM leaves the load balancing configuration in an inconsistent state.
175- Though VM is destroyed from the load balancer rule, it continues be showed as
178+ Making API calls outside the context of AutoScale, such as destroyVM, on an
179+ autoscaled VM leaves the load balancing configuration in an inconsistent state.
180+ Though VM is destroyed from the load balancer rule, it continues be showed as
176181a service assigned to a rule inside the context of AutoScale.
177182
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