Openshift

Securing Connection Between Pods in Openshift with SSL

On this post, im trying to create a simple microservices application on top of Openshift 3.11 and each services will do a simple secure connection between it by using a self-sign SSL which are managed by Openshift.

The goal of why Openshift are managing SSL certificate thru Openshift Secret is to have a rolling or rotating certificate feature on each services but can be triggered by Openshift without have to replace SSL on each services manually.

First is generate a p12 certificate by using keytool

cert>keytool -genkey -alias edw 
	-keystore edw.p12 -storetype PKCS12 
	-keyalg RSA -storepass password 
	-validity 730 -keysize 4096
What is your first and last name?
  [Unknown]:  Edwin
What is the name of your organizational unit?
  [Unknown]:  Company 01
What is the name of your organization?
  [Unknown]:  IT
What is the name of your City or Locality?
  [Unknown]:  Jakarta
What is the name of your State or Province?
  [Unknown]:  Jakarta
What is the two-letter country code for this unit?
  [Unknown]:  ID
Is CN=Edwin, OU=Company 01, O=IT, L=Jakarta, ST=Jakarta, C=ID correct?
  [no]:  yes

Next is creating two java projects which are connected one and another,

https://github.com/edwin/ssl-pods-example
https://github.com/edwin/ssl-pods-example-2

There are several part of the code that need mentioning,

First is making sure https option is active on application.properties, include our p12 certificate and make certificate password as parameterized. This parameter later on will be injected as environment variables on Openshift.

server.ssl.key-store-type=PKCS12
server.ssl.key-store=cert/edw.p12
server.ssl.key-store-password=${SSLPASSWORD}
server.ssl.key-alias=edw

server.port=8443
server.ssl.enabled=true

And the next is because we are using a custom certificate, dont forget to include it on RestTemplate.

@Configuration
public class MyRestTemplate {

    @Value("${server.ssl.key-store}")
    private String sslKeyStore;

    @Value("${server.ssl.key-store-password}")
    private String sslPassword;

    @Bean
    public RestTemplate restTemplate() throws Exception {
        KeyStore clientStore = KeyStore.getInstance("PKCS12");
        clientStore.load(new FileInputStream(sslKeyStore), sslPassword.toCharArray());

        SSLContext sslContext = SSLContextBuilder
                .create()
                .loadTrustMaterial(clientStore, new TrustSelfSignedStrategy())
                .build();
        SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext, NoopHostnameVerifier.INSTANCE);
        HttpClient httpClient = HttpClients.custom()
                .setSSLSocketFactory(socketFactory)
                .build();
        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory(httpClient);

        return new RestTemplate(factory);
    }
}

Deploy those two application to Openshift,

oc new-app registry.access.redhat.com/openjdk/openjdk-11-rhel7~https://github.com/edwin/ssl-pods-example

oc new-app registry.access.redhat.com/openjdk/openjdk-11-rhel7~https://github.com/edwin/ssl-pods-example-2

Deploy certificate as OCP Secret and mount it as a volume on our application,

oc create secret generic cert --from-file=cert\edw.p12

oc set volume dc ssl-pods-example --add -t secret -m /deployments/cert --name cert --secret-name cert
oc set volume dc ssl-pods-example-2 --add -t secret -m /deployments/cert --name cert --secret-name cert

And our certificate password as OCP Secret and inject it as environment variable to our application

oc create secret generic sslpassword --from-literal=SSLPASSWORD=password

oc set env dc ssl-pods-example --from=secret/sslpassword 
oc set env dc ssl-pods-example-2 --from=secret/sslpassword 

After all deployed on OCP, next is give a route for our application. Im using re-encrypt method for ensuring an end to end encryption within the app. In order to do so, we need to include our application CA certificate as our route’s destination certificate. We can do so by exporting our certificate from p12 file using this command,

keytool -exportcert -keystore edw.p12 -storetype PKCS12 -storepass password -alias edw -file edw.crt -rfc

And paste the certificate on our route,

The end result would be like below image,

And as you can see, we are using certificate from end to end for securing our connection.

Deploy a New Application and Building It Using Openshift S2I Feature and a Custom Base Image

Lots of ways to deploy apps to Openshift, one of it is by using oc new-app command. We are trying now to create a new app using corresponding command, but specifying a custom base image for it. For this example, im using a OpenJDK 11 and RHEL 7 base image.

The command is quite easy, run it on your code folder

D:\source> oc new-app registry.access.redhat.com/openjdk/openjdk-11-rhel7~. --name=spring-boot-2

D:\source> oc start-build spring-boot-2 --from-dir=.

It will create a BuildConfig with the name of spring-boot-2,

D:\source> oc get bc spring-boot-2
NAME            TYPE      FROM      LATEST
spring-boot-2   Source    Binary    3

We can see the detail of our BuildConfig by running this command,

D:\source> oc describe bc spring-boot-2

....
Strategy:       Source
From Image:     ImageStreamTag openjdk-11-rhel7:latest
Output to:      ImageStreamTag spring-boot-2:latest
Binary:         provided on build
....

And if we have some code change and want to redeploy, we can run this command

D:\source> oc start-build spring-boot-2 --from-dir=.

It will rebuild the whole image, and using new code which are uploaded from existing source directory.

[Openshift] Adding a NodeSelector on the Fly

This is snippet code for adding a specific nodeselector to a rc (ReplicationConfig)

oc patch rc simple-helloworld -p '{"spec": {"template": {"spec": {"nodeSelector": {"infra": "my-infra-node"}}}}}' -n dev

The same code should work for other type, such as Deployment, or DeploymentConfig.

[Openshift] Changing revisionHistoryLimit on DeploymentConfig using OC Command

DeploymentConfig on Openshift, and Kubernetes, have revisionHistoryLimit variable which shows how many history a DeploymentConfig should keep. By default it stores 10 last version of application deployment, but sometimes we have to stores less number of revision for saving storage space. Therefore we need to create a hard limit for number of revisionHistoryLimit allowed.

Given below yaml structure on DC,

Based on above image we can change directly on deploymentconfig’s Yml file, but for you who allergic to Yaml (such as me), OC command is much more convenient. This is how i change existing deploymentconfig’s configuration by utilizing OC patch command

oc patch dc starter-v0 -p '{"spec":{"revisionHistoryLimit":2}}'

It will reduce number of revision to two version before,

And this is what happen when changed into one version,

oc patch dc starter-v0 -p '{"spec":{"revisionHistoryLimit":1}}'

How to Display How Many Images are Available on Our Openshift Image Registry

Openshift is a very convenient platform, not only it provides an enterprise kubernetes cluster, but also provide its own image registry bundled within it. So we can push images and deploy it to our namescpace within our cluster in a timely manner. But there are times when i need to count how many images are resides in my existing Openshift cluster. After googling quite some time, i found the solution and write it here.

First we need to check where is our Openshift image registry url,

C:\>oc project default
Already on project "default" on server "https://console.example.com:8443".

C:\>oc get route
NAME               HOST/PORT                                                PATH      SERVICES           PORT       TERMINATION   WILDCARD
docker-registry    docker-registry-default.apps.example.com              docker-registry    5000-tcp   reencrypt     None
registry-console   registry-console-default.apps.example.com             registry-console   <all>      passthrough   None

Next step is login to our oc cluster by using this command, and insert the right username and password.

oc login https://console.example.com:8443 

And see the oc login token

oc whoami -t

Use both username and token to do a simple curl to your docker registry url,

C:\>curl -X GET https://docker-registry-default.apps.example.com/v2/_catalog -k -u <my-username>:<my-token>

The result of that api contains list of images available on your Openshift’s Image Registry.