Add reusable guide for SSH key usage during Docker builds

docs/continuous-integration/shared/ssh-during-docker-build.md

@@ -0,0 +1,53 @@
+## Using SSH Keys During Docker Builds
+
+If your Dockerfile needs to perform SSH-based operations — such as cloning private Git repositories or connecting to internal services — you can securely forward an SSH key into the build using Docker BuildKit's `--ssh` feature. This allows access to sensitive resources without baking credentials into your image.
+
+> The examples below use GitHub as the SSH target, but the approach works with any SSH-based service, including internal Git servers, artifact sources, or deployment infrastructure.
+
+### 1. Enable SSH mount in your Dockerfile
+
+At the top of your Dockerfile, enable BuildKit features:
+
+```Dockerfile
+# syntax=docker/dockerfile:1.2
+...
+```
+Then use the `--mount=type=ssh` instruction with a named ID:
+
+```Dockerfile
+...
+RUN --mount=type=ssh,id=github_ssh git clone [email protected]:your-org/private-repo.git
+...
+```
+:::note
+The `id` in `--mount=type=ssh,id=...` is just a label — it can be anything, but must match what’s passed via `PLUGIN_BUILDX_OPTIONS`.
+:::
+
+### 2. Configure your Build and Push step
+Set the `PLUGIN_BUILDX_OPTIONS` environment variable to pass the SSH option:
+
+```yaml
+- step:
+    identifier: BuildAndPushDockerRegistry
+    type: BuildAndPushDockerRegistry
+    name: Build and Push Image
+    spec:
+      connectorRef: account.harnessImage
+      repo: ghcr.io/my-org/my-service
+      tags:
+        - latest
+      caching: true
+      envVariables:
+        PLUGIN_BUILDX_OPTIONS: "--ssh=github_ssh=id_rsa"
+```
+
+### 3. Reference the SSH key from Harness Secrets Manager
+
+Mount the SSH key by referencing it from Secrets Manager using the same key name (`id_rsa`):
+
+```yaml
+      secrets:
+        id_rsa: <+secrets.getValue("github_deploy_key")>
+```
+
+This setup allows your Docker build to securely perform SSH-based operations — such as cloning private Git repositories or connecting to internal services — without exposing credentials in your Docker image or scripts.

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-acr.md

@@ -11,6 +11,7 @@ redirect_from:
 ---
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 This topic explains how to configure the **Build and Push to ACR** step in a Harness CI pipeline. This step is used to build and push to [Azure Container Registry (ACR)](https://azure.microsoft.com/en-us/products/container-registry).
 
@@ -186,6 +187,8 @@ You can find the following settings on the **Advanced** tab in the step settings
 - [Failure Strategy](/docs/platform/pipelines/failure-handling/define-a-failure-strategy-on-stages-and-steps): Control what happens to your pipeline when a step fails.
 - [Use looping strategies](/docs/platform/pipelines/looping-strategies/looping-strategies-matrix-repeat-and-parallelism): Define a matrix, repeat, or parallelism strategy for an individual step.
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as:

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-docker-jfrog.md

@@ -8,6 +8,7 @@ redirect_from:
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
 import Tar from '/docs/continuous-integration/shared/build-and-push-local-tar.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 This topic explains how to use the [Build and Push an image to Docker Registry step](./build-and-push-to-docker-registry.md) to build and push an image to [JFrog Artifactory](https://www.jfrog.com/confluence/display/JFROG/JFrog+Artifactory) Docker registries.
 
@@ -242,6 +243,8 @@ Settings:
 
 [Plugin on Dockerhub](https://hub.docker.com/r/plugins/artifactory-publish-docker-buildinfo/tags)
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as:

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-docker-registry.md

@@ -12,6 +12,7 @@ canonical_url: https://www.harness.io/blog/docker-multi-stage-build
 ---
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 This topic explains how to configure the **Build and Push an image to Docker Registry** step in a Harness CI pipeline. This step creates a Docker image from a [Dockerfile](https://docs.docker.com/engine/reference/builder/) and pushes it to a Docker registry. This is one of several options for [building and pushing artifacts in Harness CI](/docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-upload-an-artifact).
 
@@ -200,11 +201,12 @@ You can find the following settings on the **Advanced** tab in the step settings
 - [Failure Strategy](/docs/platform/pipelines/failure-handling/define-a-failure-strategy-on-stages-and-steps): Control what happens to your pipeline when a step fails.
 - [Use looping strategies](/docs/platform/pipelines/looping-strategies/looping-strategies-matrix-repeat-and-parallelism): Define a matrix, repeat, or parallelism strategy for an individual step.
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as:
 
-
 - [Why do I encounter an authentication error when using V2 API](/kb/continuous-integration/continuous-integration-faqs/#why-build-and-push-steps-dont-support-v2-api-urls)
 - [What drives the Build and Push steps? What is kaniko?](/kb/continuous-integration/continuous-integration-faqs/#what-drives-the-build-and-push-steps-what-is-kaniko)
 - [Does a kaniko build use images cached locally on the node? Can I enable caching for kaniko?](/kb/continuous-integration/continuous-integration-faqs/#does-a-kaniko-build-use-images-cached-locally-on-the-node-can-i-enable-caching-for-kaniko)

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-ecr-step-settings.md

@@ -12,6 +12,7 @@ redirect_from:
 ---
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 [Amazon ECR](https://docs.aws.amazon.com/AmazonECR/latest/userguide/what-is-ecr.html) is a fully managed service from AWS that you can use to store and manage Docker images securely and reliably. In addition, ECR provides a simple web-based interface for creating, managing, and sharing Docker images and integrating them with other AWS services. For more information, go to the AWS documentation on [Pushing a Docker image](https://docs.aws.amazon.com/AmazonECR/latest/userguide/docker-push-ecr-image.html).
 
@@ -248,6 +249,8 @@ You can find the following settings on the **Advanced** tab in the step settings
 - [Failure Strategy](/docs/platform/pipelines/failure-handling/define-a-failure-strategy-on-stages-and-steps): Control what happens to your pipeline when a step fails.
 - [Use looping strategies](/docs/platform/pipelines/looping-strategies/looping-strategies-matrix-repeat-and-parallelism): Define a matrix, repeat, or parallelism strategy for an individual step.
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as:

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-gar.md

@@ -8,6 +8,7 @@ redirect_from:
 ---
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 This topic explains how to configure the **Build and Push to GAR** step in a Harness CI pipeline. This step is used to build and push to [Google Artifact Registry (GAR)](https://cloud.google.com/artifact-registry).
 
@@ -194,6 +195,8 @@ You can find the following settings on the **Advanced** tab in the step settings
 - [Failure Strategy](/docs/platform/pipelines/failure-handling/define-a-failure-strategy-on-stages-and-steps): Control what happens to your pipeline when a step fails.
 - [Use looping strategies](/docs/platform/pipelines/looping-strategies/looping-strategies-matrix-repeat-and-parallelism): Define a matrix, repeat, or parallelism strategy for an individual step.
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as:

docs/continuous-integration/use-ci/build-and-upload-artifacts/build-and-push/build-and-push-to-ghcr.md

@@ -7,6 +7,7 @@ redirect_from:
 ---
 
 import Flags from '/docs/continuous-integration/shared/build-and-push-runtime-flags.md';
+import SshOps from '/docs/continuous-integration/shared/ssh-during-docker-build.md';
 
 This topic explains how to use the [Build and Push an image to Docker Registry step](./build-and-push-to-docker-registry.md) to build and push an image to [GitHub Container Registry](https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-container-registry).
 
@@ -184,6 +185,8 @@ You can find the following settings on the **Advanced** tab in the step settings
 - [Failure Strategy](/docs/platform/pipelines/failure-handling/define-a-failure-strategy-on-stages-and-steps): Control what happens to your pipeline when a step fails.
 - [Use looping strategies](/docs/platform/pipelines/looping-strategies/looping-strategies-matrix-repeat-and-parallelism): Define a matrix, repeat, or parallelism strategy for an individual step.
 
+<SshOps/>
+
 ## Troubleshoot Build and Push steps
 
 Go to the [CI Knowledge Base](/kb/continuous-integration/continuous-integration-faqs) for questions and issues related to building and pushing images, such as: