https://github.com/debianmaster/test-1111
Generated by the Red Hat Developer Launch (https://developers.redhat.com/launch)
https://github.com/debianmaster/test-1111
Last synced: 6 months ago
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Generated by the Red Hat Developer Launch (https://developers.redhat.com/launch)
- Host: GitHub
- URL: https://github.com/debianmaster/test-1111
- Owner: debianmaster
- License: apache-2.0
- Created: 2018-10-26T09:39:01.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-10-26T09:39:08.000Z (over 7 years ago)
- Last Synced: 2025-01-29T14:52:30.231Z (over 1 year ago)
- Language: HTML
- Homepage:
- Size: 31.3 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.adoc
- License: LICENSE
Awesome Lists containing this project
README
= Eclipse Vert.x Istio Circuit Breaker mission
== Purpose
Showcase Istio's Circuit Breaker via a (minimally) instrumented Eclipse Vert.x microservices.
== Prerequisites
* Openshift 3.9 cluster
* Istio
* Create a new project/namespace on the cluster. This is where your application will be deployed.
If you use _istiooc_ launch it with:
```bash
oc cluster up --istio
```
```bash
oc login -u system:admin
oc adm policy add-cluster-role-to-user admin developer --as=system:admin
oc login -u developer -p developer
```
== Environment preparation
Create a new project/namespace on the cluster. This is where your application will be deployed.
```bash
oc new-project
```
== Build and deploy the application with the Fabric8 Maven Plugin
Execute the following command to build the project and deploy it to OpenShift:
```bash
mvn clean fabric8:deploy -Popenshift
```
Configuration for FMP may be found both in pom.xml and `src/main/fabric8` files/folders.
== Build and deploy the application with the S2I
```bash
find . | grep openshiftio | grep application | xargs -n 1 oc apply -f
oc new-app --template=vertx-istio-circuit-breaker-greeting -p SOURCE_REPOSITORY_URL=https://github.com/openshiftio-vertx-boosters/vertx-istio-circuit-breaker-booster -p SOURCE_REPOSITORY_REF=master -p SOURCE_REPOSITORY_DIR=greeting-service
oc new-app --template=vertx-istio-circuit-breaker-name -p SOURCE_REPOSITORY_URL=https://github.com/openshiftio-vertx-boosters/vertx-istio-circuit-breaker-booster -p SOURCE_REPOSITORY_REF=master -p SOURCE_REPOSITORY_DIR=name-service
```
= Use Cases
== Access the application
* Run the following command to determine the appropriate URL to access our demo. Make sure you access the URL with the
HTTP scheme. HTTPS is NOT enabled by default:
+
```bash
oc create -f rules/gateway.yaml
echo "http://$(oc get route istio-ingressgateway -o jsonpath='{.spec.host}{"\n"}' -n istio-system)/breaker/greeting"
```
Open the given URL.
== Verify application behavior
1. Click on the "Start" button to issue 10 concurrent requests to the name service.
2. Click on the "Stop" button to stop the requests
3. You can change the number of concurrent requests between 1 and 20.
4. All calls go through as expected.
=== Initial Circuit Breaker configuration
1. Now apply the initial DestinationRule that activates Istio’s Circuit Breaker on the name service, configuring it to
allow a maximum of 100 concurrent connections.
```bash
oc create -f rules/initial-destination-rule.yaml -n $(oc project -q)
```
2. You can check that the DestinationRule is properly applied by executing:
```bash
oc get destinationrules.networking.istio.io
```
3. Try the application again. Since we only make up to 20 concurrent connections, the circuit breaker should not trip.
=== Restrictive Circuit Breaker configuration
1. Now apply a more restrictive DestinationRule, after having remove the initial one:
```bash
oc delete -f rules/initial-destination-rule.yaml
oc create -f rules/restrictive-destination-rule.yaml
```
2. Try the application again
Since the Circuit Breaker is now configured to only allow one concurrent connection and by default we are sending 10 to
the name service, we should now see the Circuit Breaker tripping open. However, experimentally, we observe that this does
not happen in a clear-cut fashion: the circuit is not always open. In fact, depending on how fast the server on which the
application is running, the circuit might not break open at all. The reason for this is that is the name service does
not do much and thus responds quite fast. This, in turn, leads to not having much concurrency at all.
=== Optional: fault injection
We could try to increase contention on the name service using Istio’s fault injection behavior by applying a 1-second
delay to 50% of the calls to the name service.
1. Create a new `VirtualService` for the name service to inject a processing delay:
```bash
oc create -f rules/name-with-delay.yaml
```
2. Try the application again
You should observe that this does not seem to change how often the circuit breaks open. This is due to the fact that
the injected delay actually occurs between the services. So, in essence, this only time shifts the requests, only
increasing concurrency marginally (due to the fact that only 50% of the requests are delayed). This still does not let
us observe the circuit breaking open properly.
3. For more comfort, let’s return to the original configuration by deleting the VirtualService we just introduced:
```bash
oc delete -f rules/name-with-delay.yaml
```
=== Simulate load on the name service
We need to increase contention on the name service in order to have enough concurrent connections to trip open the
circuit breaker. We can accomplish this by simulating load on the name service by asking it to introduce a random
processing time. To accomplish this:
1. Stop the requests (if that wasn’t already the case)
2. Checking the "Simulate load" checkbox
3. Start the requests.
You should now observe the circuit breaking open by observing lots of `Hello, Fallback!` messages.
== Undeploy the application
=== With Fabric8 Maven Plugin (FMP)
```bash
mvn fabric8:undeploy
```
=== Remove the namespace
This will delete the project from the OpenShift cluster.
```bash
oc delete project
```