rgolangh commented on code in PR #611:
URL:
https://github.com/apache/incubator-kie-kogito-docs/pull/611#discussion_r1547491222
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serverlessworkflow/modules/ROOT/pages/cloud/operator/add-custom-ca-to-a-pod.md:
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+# Adding a custom CA Certificate to a Container Running Java
+
+If you're working with containers running Java applications and need to add a
CA (Certificate Authority) certificate for secure communication, you can follow
these steps. This guide assumes you are familiar with containers and have basic
knowledge of working with YAML files.
+
+Table Of Contents:
+1. [Problem Space](#problem-space)
+2. [Step 1: Obtain the CA Certificate](#step-1-obtain-the-ca-certificate)
+3. [Step 2: Prepare a trust store in an
init-container](#step-2-prepare-a-trust-store-in-an-init-container)
+4. [Step 3: Configure Java to load the new
keystore](#step-3-configure-Java-to-load-the-new-keystore)
+5. [Full working example](#full-working-example)
+6. [Serverless Workflow Example](#serverless-workflow-example)
+
+## Problem Space
+
+If you have a containerized Java application that connects to an SSL endpoint
with a certificate signed by an internal authority (like SSL terminated routes
on a cluster) you need to make sure Java can read the CA Authority certificate
and verify it. Java unfortunately doesn't load certificates directly, but
rather store them in a [keystore][keystore].
+
+The default trust store under `$JAVA_HOME/lib/security/cacerts` contains only
CA's which are shipped with the Java distribution and there's the `keytool`
tool that knows how manipulate those key stores.
+The containerized application may not know the CA certificate in build time,
and so we need to add it to the trust-store in deployment. To automate that we
can a combination of an init-container and a shared directory to pass the
mutated trust store to the container before it runs. Let's run this step by
step:
+
+## Step 1: Obtain the CA Certificate
+
+Before proceeding, ensure you have the CA certificate file (in PEM format)
that you want to add to the Java container. If you don't have it, you may need
to obtain it from your system administrator or certificate provider.
+
+For the purpose of this guide we would take the k8s cluster root CA that is
automatically deployed into every container under
`/var/run/secrets/kubernetes.io/serviceaccount/ca.crt`
+
+## Step 2: Prepare a trust store in an init-container
+
+Add or amend this volumes and init-container snippet to your pod spec or
podTemplate in a deployment:
+
+```yaml
+spec:
+ volumes:
+ - name: new-cacerts
+ emptyDir: {}
+ initContainers:
+ - name: add-kube-root-ca-to-cacerts
+ image: registry.access.redhat.com/ubi9/openjdk-21
+ volumeMounts:
+ - mountPath: /opt/new-cacerts
+ name: new-cacerts
+ command:
+ - /bin/bash
+ - -c
+ - |
+ cp $JAVA_HOME/lib/security/cacerts /opt/new-cacerts/
+ chmod +w /opt/new-cacerts/cacerts
+ keytool -importcert -no-prompt -keystore /opt/new-cacerts/cacerts
-storepass changeit -file /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
+```
+
+The default keystore under $JAVA_HOME is part of the container image and is
not mutable. We have to create the mutated copy to a shared volume, hence the
'new-cacerts' one.
+
+## Step 3: Configure Java to load the new keystore
+
+Here we would just mount the new, modified cacerts into the default location
where the JVM looks at.
+The example main uses the standard http client so alternative we could mount
the cacerts to a different location and
+configure the Java runtime to load the new keystore with a system property
`-Djavax.net.ssl.trustStore`.
+Note that libraries like resteasy don't respect that flag and may need to
programmatically set the trust store location.
+
+```yaml
+ containers:
+ - command:
+ - /bin/bash
+ - -c
+ - |
+ curl -L
https://gist.githubusercontent.com/rgolangh/b949d8617709d10ba6c690863e52f259/raw/bdea4d757a05b75935bbb57f3f05635f13927b34/Main.java
-o curl.java
+ java curl.java https://kubernetes
+ image: registry.access.redhat.com/ubi9/openjdk-21
+ imagePullPolicy: Always
+ name: openjdk-21
+ volumeMounts:
+ - mountPath: /lib/jvm/java-21/lib/security
+ name: new-cacerts
+ readOnly: true
+ - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
+ name: kube-api-access-5npmd
+ readOnly: true
+```
+
+Notice the volume mount of the previously mutate keystore.
+
+
+## Full working example
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+ name: root-ca-to-cacerts
+spec:
+ initContainers:
+ - name: add-kube-root-ca-to-cacerts
+ image: registry.access.redhat.com/ubi9/openjdk-21
+ volumeMounts:
+ - mountPath: /opt/new-cacerts
+ name: new-cacerts
+ command:
+ - /bin/bash
+ - -c
+ - |
+ cp $JAVA_HOME/lib/security/cacerts /opt/new-cacerts/
+ chmod +w /opt/new-cacerts/cacerts
+ keytool -importcert -no-prompt -keystore /opt/new-cacerts/cacerts
-storepass changeit -file /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
+ containers:
+ - command:
+ - /bin/bash
+ - -c
+ - |
+ curl -L
https://gist.githubusercontent.com/rgolangh/b949d8617709d10ba6c690863e52f259/raw/bdea4d757a05b75935bbb57f3f05635f13927b34/Main.java
-o curl.java
Review Comment:
so i'll add both this small main, and the example workflow or pod yaml to
the examples
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