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The following commit(s) were added to refs/heads/master by this push:
new e6f9bc7 Moved policies CAMP specific content to external file to
allow future overwritings of this
e6f9bc7 is described below
commit e6f9bc7d098a262884098e24ad397711e95249ba
Author: iuliana <[email protected]>
AuthorDate: Wed Aug 11 12:08:18 2021 +0100
Moved policies CAMP specific content to external file to allow future
overwritings of this
---
guide/start/{policies.md => _policies.camp.md} | 137 ++++---
guide/start/policies.md | 496 +------------------------
2 files changed, 64 insertions(+), 569 deletions(-)
diff --git a/guide/start/policies.md b/guide/start/_policies.camp.md
similarity index 89%
copy from guide/start/policies.md
copy to guide/start/_policies.camp.md
index 7537dd4..ce3d4b6 100644
--- a/guide/start/policies.md
+++ b/guide/start/_policies.camp.md
@@ -1,19 +1,8 @@
----
-title: Getting Started - Policies
-title_in_menu: Policies
-layout: website-normal
----
-
-## A Clustered Example
-
-We'll now look at a more complex example that better shows the capabilities of
Brooklyn, including
-management of a running clustered application.
-
-Below is the annotated blueprint. [Download the
blueprint](example_yaml/mycluster.yaml) into a
-text file, `mycluster.yaml`, in your workspace. *Before* you create an
application with it,
+Below is the annotated blueprint. [Download the
blueprint](example_yaml/mycluster.yaml) into a
+text file, `mycluster.yaml`, in your workspace. *Before* you create an
application with it,
review and/or change the the location where the application will be deployed.
-You will need four machines for this example: one for the load-balancer
(nginx), and three for the
+You will need four machines for this example: one for the load-balancer
(nginx), and three for the
Tomcat cluster (but you can reduce this by changing the `maxPoolSize` below).
<div class="usermanual-pdf-include started-pdf-include" style="display: none;">
@@ -21,28 +10,28 @@ Tomcat cluster (but you can reduce this by changing the
`maxPoolSize` below).
name: Tomcat Cluster
location:
- byon:
- user: vagrant
- password: vagrant
- hosts:
- - 10.10.10.101
- - 10.10.10.102
- - 10.10.10.103
- - 10.10.10.104
-
+byon:
+user: vagrant
+password: vagrant
+hosts:
+- 10.10.10.101
+- 10.10.10.102
+- 10.10.10.103
+- 10.10.10.104
+
services:
- type: org.apache.brooklyn.entity.group.DynamicCluster
name: Cluster
id: cluster
brooklyn.config:
- cluster.initial.size: 1
- dynamiccluster.memberspec:
- $brooklyn:entitySpec:
- type: org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- name: Tomcat Server
- brooklyn.config:
- wars.root:
http://search.maven.org/remotecontent?filepath=org/apache/brooklyn/example/brooklyn-example-hello-world-webapp/0.8.0-incubating/brooklyn-example-hello-world-webapp-0.8.0-incubating.war
-
+ cluster.initial.size: 1
+ dynamiccluster.memberspec:
+ $brooklyn:entitySpec:
+ type: org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
+ name: Tomcat Server
+ brooklyn.config:
+ wars.root:
http://search.maven.org/remotecontent?filepath=org/apache/brooklyn/example/brooklyn-example-hello-world-webapp/0.8.0-incubating/brooklyn-example-hello-world-webapp-0.8.0-incubating.war
+
brooklyn.policies:
- type: org.apache.brooklyn.policy.ha.ServiceRestarter
brooklyn.config:
@@ -51,12 +40,12 @@ services:
- type: org.apache.brooklyn.policy.ha.ServiceFailureDetector
brooklyn.config:
entityFailed.stabilizationDelay: 30s
-
+
brooklyn.policies:
- - type: org.apache.brooklyn.policy.ha.ServiceReplacer
-
- - type: org.apache.brooklyn.policy.autoscaling.AutoScalerPolicy
- brooklyn.config:
+ - type: org.apache.brooklyn.policy.ha.ServiceReplacer
+
+ - type: org.apache.brooklyn.policy.autoscaling.AutoScalerPolicy
+ brooklyn.config:
metric: webapp.reqs.perSec.perNode
metricUpperBound: 3
metricLowerBound: 1
@@ -65,8 +54,8 @@ services:
maxPoolSize: 3
brooklyn.enrichers:
- - type: org.apache.brooklyn.enricher.stock.Aggregator
- brooklyn.config:
+ - type: org.apache.brooklyn.enricher.stock.Aggregator
+ brooklyn.config:
enricher.sourceSensor: $brooklyn:sensor("webapp.reqs.perSec.windowed")
enricher.targetSensor: $brooklyn:sensor("webapp.reqs.perSec.perNode")
enricher.aggregating.fromMembers: true
@@ -75,9 +64,9 @@ services:
- type: org.apache.brooklyn.entity.proxy.nginx.NginxController
name: Load Balancer (nginx)
brooklyn.config:
- loadbalancer.serverpool: $brooklyn:entity("cluster")
- nginx.sticky: false
-{% endhighlight %}
+ loadbalancer.serverpool: $brooklyn:entity("cluster")
+ nginx.sticky: false
+ {% endhighlight %}
</div>
<!-- WARNING: if modifying either mycluster.yaml or the yaml below, be sure to
keep them both in-sync -->
@@ -90,7 +79,7 @@ services:
<div class="ann_play fa fa-play-circle-o"></div>
</div></div></div>
<div class="code_viewer">
-
+
<div class="block">
<div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
<div class="short">
@@ -279,8 +268,8 @@ if (window.$ != null) {
## The Tomcat Cluster
-The `DynamicCluster` can dynamically increase or decrease the number of
members. Resizing the
-cluster can either be carried out manually via effectors or automatically by
attaching an
+The `DynamicCluster` can dynamically increase or decrease the number of
members. Resizing the
+cluster can either be carried out manually via effectors or automatically by
attaching an
`AutoScalerPolicy`.
It is configured with a `dynamiccluster.memberspec`, which defines the type
and configuration of members
@@ -309,41 +298,41 @@ br application
nGY58ZZN Tomcat Cluster RUNNING Mf0CJac6
</pre>
-You can view the list of entities within the cluster with the command below
(which drills into the
+You can view the list of entities within the cluster with the command below
(which drills into the
application named "Tomcat Cluster", then into its child entity named
"Cluster", and then lists its
entities):
{% highlight bash %}
br application "Tomcat Cluster" entity "Cluster" entity
{% endhighlight %}
-
+
<pre>
Id Name Type
dYfUvLIw quarantine org.apache.brooklyn.entity.group.QuarantineGroup
tOpMeYYr Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
</pre>
-The "quarantine" entity is used when Tomcat servers fail to start correctly -
this entity is by
+The "quarantine" entity is used when Tomcat servers fail to start correctly -
this entity is by
default added to the quarantine group, where it can later be investigated.
This can be disabled using
the configuration `dynamiccluster.quarantineFailedEntities: false`.
## Tomcat auto-repair
-Each Tomcat entity has a `ServiceFailureDetector` enricher and a
`ServiceRestarter` policy.
+Each Tomcat entity has a `ServiceFailureDetector` enricher and a
`ServiceRestarter` policy.
-An *enricher* generates new events or sensor values (metrics) for the entity
by modifying or
-aggregating data from one or more other sensors. A *policy* coordinates the
runtime management of
-entities by carrying out actions, initiated by specific triggers. Policies are
often used to keep
+An *enricher* generates new events or sensor values (metrics) for the entity
by modifying or
+aggregating data from one or more other sensors. A *policy* coordinates the
runtime management of
+entities by carrying out actions, initiated by specific triggers. Policies are
often used to keep
the system in a healthy state, such as handling failures and auto-scaling.
-The built-in functionality of the Tomcat entity is to use the "service.state"
sensor to report
+The built-in functionality of the Tomcat entity is to use the "service.state"
sensor to report
its status. It will be "on-fire" when a failure is detected, or "running" when
healthy, or one of
-the other lifecycle states such as "starting", "stopping" or "stopped".
+the other lifecycle states such as "starting", "stopping" or "stopped".
-The `ServiceFailureDetector` enricher emits an "Entity Failed" event whenever
a failure is detected,
-and similarly an "Entity Recovered" event when recovered. The configuration
option
-`serviceOnFireStabilizationDelay` will suppress reporting of failure until the
entity is detected
+The `ServiceFailureDetector` enricher emits an "Entity Failed" event whenever
a failure is detected,
+and similarly an "Entity Recovered" event when recovered. The configuration
option
+`serviceOnFireStabilizationDelay` will suppress reporting of failure until the
entity is detected
as failed for the given duration. This is very useful so as not to over-react
to temporary failures.
The `ServiceRestarter` policy attaches to an entity in order to restart the
service on failure. If
@@ -355,7 +344,7 @@ Tomcat on the vagrant VMs named "byon1" to "byon4":
{% highlight bash %}
for i in byon{1..4}; do
- vagrant ssh ${i} --command 'ps aux | grep -i tomcat | grep -v grep | awk
'\''{print $2}'\'' | xargs kill -9'
+vagrant ssh ${i} --command 'ps aux | grep -i tomcat | grep -v grep | awk
'\''{print $2}'\'' | xargs kill -9'
done
{% endhighlight %}
@@ -391,17 +380,17 @@ After the given `stabilizationDelay`, the Tomcat server
will be automatically re
## Cluster auto-replace
-The cluster has a `ServiceReplacer` policy. This attaches to a
`DynamicCluster` and replaces a
+The cluster has a `ServiceReplacer` policy. This attaches to a
`DynamicCluster` and replaces a
failed member; if this fails, it sets the Cluster state to on-fire.
-To simulate a terminal failure of a member, repeatedly kill the process (using
the command
+To simulate a terminal failure of a member, repeatedly kill the process (using
the command
above).
The Tomcat server should be replaced by a new member of the cluster, and then
the old failed member
removed.
You can view the list of Tomcat servers in the cluster with the command below
(which drills into the
-application named "Tomcat Cluster", then into its child entity named
"Cluster", and then lists the
+application named "Tomcat Cluster", then into its child entity named
"Cluster", and then lists the
child entities):
{% highlight bash %}
@@ -418,30 +407,30 @@ br application "Tomcat Cluster" entity "Cluster" entity
## Auto-scaling
-The `AutoScalerPolicy` attaches to a `Resizable` entity (in this case the
`DynamicCluster`) and
-dynamically adjusts its size in response to keeping a metric within a given
range. It adds/removes
+The `AutoScalerPolicy` attaches to a `Resizable` entity (in this case the
`DynamicCluster`) and
+dynamically adjusts its size in response to keeping a metric within a given
range. It adds/removes
members (e.g. Tomcat instances) automatically.
-In this example policy, the `metricUpperBound` for requests per second per
server is configured
-very low at just 3. This makes it simple to trigger auto-scaling. The
`resizeUpStabilizationDelay`
+In this example policy, the `metricUpperBound` for requests per second per
server is configured
+very low at just 3. This makes it simple to trigger auto-scaling. The
`resizeUpStabilizationDelay`
of 2 seconds means the load must be sustained for at least that length of
time. The
-`resizeDownStabilizationDelay` of 1 minute means there must be low load for a
full one minute
+`resizeDownStabilizationDelay` of 1 minute means there must be low load for a
full one minute
before it will scale back down.
Find the URL of the load-balancer - see the `NginxController` sensor named
`main.uri`.
To generate load, you can use your web-browser by repeatedly refreshing that
page. Alternatively,
-you could use a load generator like jmeter, or use a script such as the one
shown below
+you could use a load generator like jmeter, or use a script such as the one
shown below
(changing URL for the URL of your load-balancer):
{% highlight bash %}
URL=http://10.10.10.101:8000/
for i in {1..600}; do
- for j in {1..50}; do
- curl --fail --silent ${URL} > /dev/null || echo "Curl failed with exit
code $?"
- done
- echo "Finished batch $i"
- sleep 1
+for j in {1..50}; do
+curl --fail --silent ${URL} > /dev/null || echo "Curl failed with exit code $?"
+done
+echo "Finished batch $i"
+sleep 1
done
{% endhighlight %}
@@ -466,9 +455,9 @@ br application "Tomcat Cluster" entity "Cluster" entity
"Tomcat Server" sensor
webapp.url URL
"http://10.10.10.103:18082/";
...
</pre>
-
+
You can look at the average requests per second on the cluster with the
command:
-
+
{% highlight bash %}
br application "Tomcat Cluster" entity "Cluster" sensor
"webapp.reqs.perSec.perNode"
{% endhighlight %}
@@ -492,7 +481,7 @@ br application "Tomcat Cluster" entity "Cluster" entity
CpabLxZE Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
</pre>
-Cancel the curl commands (or wait for them to finish), and then wait for the
one minute
+Cancel the curl commands (or wait for them to finish), and then wait for the
one minute
`resizeDownStabilizationDelay`. The cluster will scale back to the minimum one
instance.
{% highlight bash %}
diff --git a/guide/start/policies.md b/guide/start/policies.md
index 7537dd4..fe9a613 100644
--- a/guide/start/policies.md
+++ b/guide/start/policies.md
@@ -9,498 +9,4 @@ layout: website-normal
We'll now look at a more complex example that better shows the capabilities of
Brooklyn, including
management of a running clustered application.
-Below is the annotated blueprint. [Download the
blueprint](example_yaml/mycluster.yaml) into a
-text file, `mycluster.yaml`, in your workspace. *Before* you create an
application with it,
-review and/or change the the location where the application will be deployed.
-
-You will need four machines for this example: one for the load-balancer
(nginx), and three for the
-Tomcat cluster (but you can reduce this by changing the `maxPoolSize` below).
-
-<div class="usermanual-pdf-include started-pdf-include" style="display: none;">
-{% highlight yaml %}
-name: Tomcat Cluster
-
-location:
- byon:
- user: vagrant
- password: vagrant
- hosts:
- - 10.10.10.101
- - 10.10.10.102
- - 10.10.10.103
- - 10.10.10.104
-
-services:
-- type: org.apache.brooklyn.entity.group.DynamicCluster
- name: Cluster
- id: cluster
- brooklyn.config:
- cluster.initial.size: 1
- dynamiccluster.memberspec:
- $brooklyn:entitySpec:
- type: org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- name: Tomcat Server
- brooklyn.config:
- wars.root:
http://search.maven.org/remotecontent?filepath=org/apache/brooklyn/example/brooklyn-example-hello-world-webapp/0.8.0-incubating/brooklyn-example-hello-world-webapp-0.8.0-incubating.war
-
- brooklyn.policies:
- - type: org.apache.brooklyn.policy.ha.ServiceRestarter
- brooklyn.config:
- failOnRecurringFailuresInThisDuration: 5m
- brooklyn.enrichers:
- - type: org.apache.brooklyn.policy.ha.ServiceFailureDetector
- brooklyn.config:
- entityFailed.stabilizationDelay: 30s
-
- brooklyn.policies:
- - type: org.apache.brooklyn.policy.ha.ServiceReplacer
-
- - type: org.apache.brooklyn.policy.autoscaling.AutoScalerPolicy
- brooklyn.config:
- metric: webapp.reqs.perSec.perNode
- metricUpperBound: 3
- metricLowerBound: 1
- resizeUpStabilizationDelay: 2s
- resizeDownStabilizationDelay: 1m
- maxPoolSize: 3
-
- brooklyn.enrichers:
- - type: org.apache.brooklyn.enricher.stock.Aggregator
- brooklyn.config:
- enricher.sourceSensor: $brooklyn:sensor("webapp.reqs.perSec.windowed")
- enricher.targetSensor: $brooklyn:sensor("webapp.reqs.perSec.perNode")
- enricher.aggregating.fromMembers: true
- transformation: average
-
-- type: org.apache.brooklyn.entity.proxy.nginx.NginxController
- name: Load Balancer (nginx)
- brooklyn.config:
- loadbalancer.serverpool: $brooklyn:entity("cluster")
- nginx.sticky: false
-{% endhighlight %}
-</div>
-
-<!-- WARNING: if modifying either mycluster.yaml or the yaml below, be sure to
keep them both in-sync -->
-
-<div class="jumobotron annotated_blueprint" markdown="1">
- <div class="code_scroller">
- <div class="initial_notice"><div><div>
- Hover over an element to learn more
- <div class="ann_light">This message will go away in <span
id="countdown">3s</span></div>
- <div class="ann_play fa fa-play-circle-o"></div>
- </div></div></div>
- <div class="code_viewer">
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Describe your application
- </div>
- <div class="long"><p>
- Start by giving it a name, optionally adding a version and other
metadata.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div><span class="ann_highlight">name: Tomcat Cluster</span>
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Define the target location
- </div>
- <div class="long"><p>
- Blueprints are designed for portability.
- Pick from dozens of clouds in hundreds of datacenters.
- Or machines with fixed IP addresses, localhost,
- Docker on <a href="http://clocker.io";>Clocker</a>, etc.
- </p><p>
- Here we target pre-existing Vagrant VMs.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div><span class="ann_highlight">location:</span>
- byon:
- user: vagrant
- password: vagrant
- hosts:
- - 10.10.10.101
- - 10.10.10.102
- - 10.10.10.103
- - 10.10.10.104
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Define a cluster
- </div>
- <div class="long"><p>
- Choose your cluster type.
- </p><p>
- Customize with config keys, such as the initial size. Define the
members of the cluster.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div>services:
-<span class="ann_highlight">- type:
org.apache.brooklyn.entity.group.DynamicCluster</span>
- name: Cluster
- id: cluster
- brooklyn.config:
- cluster.initial.size: 1
- dynamiccluster.memberspec:
- $brooklyn:entitySpec:
- type: org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- name: Tomcat Server
- brooklyn.config:
- wars.root:
http://search.maven.org/remotecontent?filepath=org/apache/brooklyn/example/brooklyn-example-hello-world-webapp/0.8.0-incubating/brooklyn-example-hello-world-webapp-0.8.0-incubating.war
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Tomcat auto-repair policy
- </div>
- <div class="long"><p>
- For each member of the cluster, include an auto-repair policy that
restarts the service.
- </p><p>
- If it repeatedly fails, the service will be propagate a failure
notification.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div> brooklyn.policies:
-<span class="ann_highlight"> - type:
org.apache.brooklyn.policy.ha.ServiceRestarter</span>
- brooklyn.config:
- failOnRecurringFailuresInThisDuration: 5m
- brooklyn.enrichers:
-<span class="ann_highlight"> - type:
org.apache.brooklyn.policy.ha.ServiceFailureDetector</span>
- brooklyn.config:
- entityFailed.stabilizationDelay: 30s
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Cluster auto-replace policy
- </div>
- <div class="long"><p>
- On the cluster, handle a member's failure by replacing it with a
brand new member.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div> brooklyn.policies:
-<span class="ann_highlight"> - type:
org.apache.brooklyn.policy.ha.ServiceReplacer</span>
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Auto-scaling policy
- </div>
- <div class="long"><p>
- Auto-scale the cluster, based on runtime metrics of the cluster.
- </p><p>
- For a simplistic demonstration, this uses requests per second.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div><span class="ann_highlight"> - type:
org.apache.brooklyn.policy.autoscaling.AutoScalerPolicy</span>
- brooklyn.config:
- metric: webapp.reqs.perSec.perNode
- metricUpperBound: 3
- metricLowerBound: 1
- resizeUpStabilizationDelay: 2s
- resizeDownStabilizationDelay: 1m
- maxPoolSize: 3
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Aggregate the member's metrics.
- </div>
- <div class="long"><p>
- Add an enricher to aggregate the member's requests per second.
- </p><p>
- For a simplistic demonstration, this uses requests per second.
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div> brooklyn.enrichers:
-<span class="ann_highlight"> - type:
org.apache.brooklyn.enricher.stock.Aggregator</span>
- brooklyn.config:
- enricher.sourceSensor: $brooklyn:sensor("webapp.reqs.perSec.windowed")
- enricher.targetSensor: $brooklyn:sensor("webapp.reqs.perSec.perNode")
- enricher.aggregating.fromMembers: true
- transformation: average
-</div></div>
-
-<div class="block">
- <div class="annotations_wrapper1"><div class="annotations_wrapper2"><div
class="annotations">
- <div class="short">
- Define a load-balancer
- </div>
- <div class="long"><p>
- Add a load balancer entity.
- </p><p>
- Configure it to monitor and balance across the cluster of Tomcat
servers, which was given:
- </p><p>
- id: cluster
- </p></div>
- </div><div class="connector"><div> </div></div></div></div>
-<div><span class="ann_highlight">- type:
org.apache.brooklyn.entity.proxy.nginx.NginxController</span>
- name: Load Balancer (nginx)
- brooklyn.config:
- loadbalancer.serverpool: $brooklyn:entity("cluster")
- nginx.sticky: false
-</div></div>
-
- </div></div>
-</div>
-
-<script language="JavaScript" type="application/javascript">
-
-{% comment %}
-See blueprint-tour.md for where this CSS/javascript was copied from.
-{% endcomment %}
-
-if (window.$ != null) {
- $(function() {
- maxCodeWidth = Math.max.apply(Math, $(".annotated_blueprint div.block
> div:last-child").map(function(){ return this.scrollWidth; }).get());
- $(".annotated_blueprint div.block").width(maxCodeWidth);
- })
-
- $(".annotated_blueprint .code_scroller .initial_notice >
div").height($(".annotated_blueprint .code_scroller .code_viewer").height());
- $(".annotated_blueprint .code_scroller .initial_notice >
div").width($(".annotated_blueprint .code_scroller").width());
- $(".annotated_blueprint .code_scroller").hover(function() {
- $(".annotated_blueprint .initial_notice").css("display", "none");
- });
- $(function() {
- setTimeout(function() { $(".annotated_blueprint
.initial_notice").hide(400); }, 3000);
- setTimeout(function() { $(".annotated_blueprint
#countdown").text("2s"); }, 1000);
- setTimeout(function() { $(".annotated_blueprint
#countdown").text("1s"); }, 2000);
- });
- }
-</script>
-
-
-## The Tomcat Cluster
-
-The `DynamicCluster` can dynamically increase or decrease the number of
members. Resizing the
-cluster can either be carried out manually via effectors or automatically by
attaching an
-`AutoScalerPolicy`.
-
-It is configured with a `dynamiccluster.memberspec`, which defines the type
and configuration of members
-in the cluster. In our example, each is a Tomcat server with a WAR deployed at
the root URL.
-
-Deploy the app:
-
-{% highlight bash %}
-br deploy mycluster.yaml
-{% endhighlight %}
-
-<pre>
- Id: nGY58ZZN
- Name: Tomcat Cluster
- Status: In progress
-</pre>
-
-And wait for the app to be running, viewing its state with:
-
-{% highlight bash %}
-br application
-{% endhighlight %}
-
-<pre>
- Id Name Status Location
- nGY58ZZN Tomcat Cluster RUNNING Mf0CJac6
-</pre>
-
-You can view the list of entities within the cluster with the command below
(which drills into the
-application named "Tomcat Cluster", then into its child entity named
"Cluster", and then lists its
-entities):
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity
-{% endhighlight %}
-
-<pre>
- Id Name Type
- dYfUvLIw quarantine org.apache.brooklyn.entity.group.QuarantineGroup
- tOpMeYYr Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
-</pre>
-
-The "quarantine" entity is used when Tomcat servers fail to start correctly -
this entity is by
-default added to the quarantine group, where it can later be investigated.
This can be disabled using
-the configuration `dynamiccluster.quarantineFailedEntities: false`.
-
-
-## Tomcat auto-repair
-
-Each Tomcat entity has a `ServiceFailureDetector` enricher and a
`ServiceRestarter` policy.
-
-An *enricher* generates new events or sensor values (metrics) for the entity
by modifying or
-aggregating data from one or more other sensors. A *policy* coordinates the
runtime management of
-entities by carrying out actions, initiated by specific triggers. Policies are
often used to keep
-the system in a healthy state, such as handling failures and auto-scaling.
-
-The built-in functionality of the Tomcat entity is to use the "service.state"
sensor to report
-its status. It will be "on-fire" when a failure is detected, or "running" when
healthy, or one of
-the other lifecycle states such as "starting", "stopping" or "stopped".
-
-The `ServiceFailureDetector` enricher emits an "Entity Failed" event whenever
a failure is detected,
-and similarly an "Entity Recovered" event when recovered. The configuration
option
-`serviceOnFireStabilizationDelay` will suppress reporting of failure until the
entity is detected
-as failed for the given duration. This is very useful so as not to over-react
to temporary failures.
-
-The `ServiceRestarter` policy attaches to an entity in order to restart the
service on failure. If
-there are subsequent failures within a configurable time interval, or if the
restart fails, the
-service entity is marked as failed and no futher restarts are attempted.
-
-Try killing the Tomcat process for one of the members in the cluster. The
command below will kill
-Tomcat on the vagrant VMs named "byon1" to "byon4":
-
-{% highlight bash %}
-for i in byon{1..4}; do
- vagrant ssh ${i} --command 'ps aux | grep -i tomcat | grep -v grep | awk
'\''{print $2}'\'' | xargs kill -9'
-done
-{% endhighlight %}
-
-You can view the state of the Tomcat server with the command below (which
drills into the
-application named "Tomcat Cluster", then into its child entity named
"Cluster", and then into the
-first member of the cluster named "Tomcat Server"):
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity "Tomcat Server"
-{% endhighlight %}
-
-<pre>
- Id: tOpMeYYr
- Name: Tomcat Server
- Status: ON_FIRE
- ServiceUp: false
- Type: org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- CatalogItemId:
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer:0.0.0.SNAPSHOT
-</pre>
-
-<!-- COMMENT:
-You can view its activity, to see the call to restart, using:
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity "Tomcat Server"
activity
-{% endhighlight %}
-
-TODO Why doesn't the restart() show in the activity view?!
--->
-
-After the given `stabilizationDelay`, the Tomcat server will be automatically
restarted.
-
-
-## Cluster auto-replace
-
-The cluster has a `ServiceReplacer` policy. This attaches to a
`DynamicCluster` and replaces a
-failed member; if this fails, it sets the Cluster state to on-fire.
-
-To simulate a terminal failure of a member, repeatedly kill the process (using
the command
-above).
-
-The Tomcat server should be replaced by a new member of the cluster, and then
the old failed member
-removed.
-
-You can view the list of Tomcat servers in the cluster with the command below
(which drills into the
-application named "Tomcat Cluster", then into its child entity named
"Cluster", and then lists the
-child entities):
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity
-{% endhighlight %}
-
-<pre>
- Id Name Type
- dYfUvLIw quarantine org.apache.brooklyn.entity.group.QuarantineGroup
- tOpMeYYr Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- mgoRpkKH Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
-</pre>
-
-
-## Auto-scaling
-
-The `AutoScalerPolicy` attaches to a `Resizable` entity (in this case the
`DynamicCluster`) and
-dynamically adjusts its size in response to keeping a metric within a given
range. It adds/removes
-members (e.g. Tomcat instances) automatically.
-
-In this example policy, the `metricUpperBound` for requests per second per
server is configured
-very low at just 3. This makes it simple to trigger auto-scaling. The
`resizeUpStabilizationDelay`
-of 2 seconds means the load must be sustained for at least that length of
time. The
-`resizeDownStabilizationDelay` of 1 minute means there must be low load for a
full one minute
-before it will scale back down.
-
-Find the URL of the load-balancer - see the `NginxController` sensor named
`main.uri`.
-
-To generate load, you can use your web-browser by repeatedly refreshing that
page. Alternatively,
-you could use a load generator like jmeter, or use a script such as the one
shown below
-(changing URL for the URL of your load-balancer):
-
-{% highlight bash %}
-URL=http://10.10.10.101:8000/
-for i in {1..600}; do
- for j in {1..50}; do
- curl --fail --silent ${URL} > /dev/null || echo "Curl failed with exit
code $?"
- done
- echo "Finished batch $i"
- sleep 1
-done
-{% endhighlight %}
-
-While those curl commands run in a separate terminal, you can look at the
metrics for the first
-Tomcat server using the command:
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity "Tomcat Server" sensor
-{% endhighlight %}
-
-<pre>
- Name Description
Value
- ...
- webapp.reqs.perSec.last Reqs/sec (last datapoint)
0.9980039920159681
- webapp.reqs.perSec.windowed Reqs/sec (over time window)
0.9326571333555038
- webapp.reqs.processingTime.fraction.last Fraction of time spent
processing, reported by webserver (percentage, last datapoint) "0.067%"
- webapp.reqs.processingTime.fraction.windowed Fraction of time spent
processing, reported by webserver (percentage, over time window) "0.073%"
- webapp.reqs.processingTime.max Max processing time for any
single request, reported by webserver (millis) ""
- webapp.reqs.processingTime.total Total processing time,
reported by webserver (millis) "3.12s"
- webapp.reqs.total Request count
5575
- webapp.tomcat.connectorStatus Catalina connector state name
"STARTED"
- webapp.url URL
"http://10.10.10.103:18082/";
- ...
-</pre>
-
-You can look at the average requests per second on the cluster with the
command:
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" sensor
"webapp.reqs.perSec.perNode"
-{% endhighlight %}
-
-<pre>
- 25.765557404326124
-</pre>
-
-When this value exceeds 3 for two seconds, the cluster with scale up. You can
see the new instance
-using the command:
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity
-{% endhighlight %}
-
-<pre>
- Id Name Type
- dYfUvLIw quarantine org.apache.brooklyn.entity.group.QuarantineGroup
- mgoRpkKH Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- xpLeJufy Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
- CpabLxZE Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
-</pre>
-
-Cancel the curl commands (or wait for them to finish), and then wait for the
one minute
-`resizeDownStabilizationDelay`. The cluster will scale back to the minimum one
instance.
-
-{% highlight bash %}
-br application "Tomcat Cluster" entity "Cluster" entity
-{% endhighlight %}
-
-<pre>
- Id Name Type
- dYfUvLIw quarantine org.apache.brooklyn.entity.group.QuarantineGroup
- mgoRpkKH Tomcat Server
org.apache.brooklyn.entity.webapp.tomcat.TomcatServer
-</pre>
+{% read _policies.camp.md %}
\ No newline at end of file
