From 984ecbe1d1d42cb16e2f59cc3e1fde3bc8e0c2b5 Mon Sep 17 00:00:00 2001
From: Kevin Wiesmueller <kwiesmul@redhat.com>
Date: Wed, 14 Apr 2021 14:48:22 +0200
Subject: [PATCH 1/2] support deloying with tags instead of shas

Signed-off-by: Kevin Wiesmueller <kwiesmul@redhat.com>
---
 Makefile              | 2 +-
 hack/cluster-build.sh | 2 +-
 hack/parse-shasums.sh | 5 +++++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 39ab7d0ed10a..41b2063dec07 100644
--- a/Makefile
+++ b/Makefile
@@ -114,7 +114,7 @@ build-verify:
 
 manifests:
 	hack/dockerized "CSV_VERSION=${CSV_VERSION} QUAY_REPOSITORY=${QUAY_REPOSITORY} \
-	  DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} \
+	  DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} KUBEVIRT_ONLY_USE_TAGS=${KUBEVIRT_ONLY_USE_TAGS} \
 	  IMAGE_PULL_POLICY=${IMAGE_PULL_POLICY} VERBOSITY=${VERBOSITY} PACKAGE_NAME=${PACKAGE_NAME} \
 	  KUBEVIRT_INSTALLED_NAMESPACE=${KUBEVIRT_INSTALLED_NAMESPACE} ./hack/build-manifests.sh"
 
diff --git a/hack/cluster-build.sh b/hack/cluster-build.sh
index 7aebb0250742..02646d44bc59 100755
--- a/hack/cluster-build.sh
+++ b/hack/cluster-build.sh
@@ -36,7 +36,7 @@ echo "Building ..."
 # Build everyting and publish it
 ${KUBEVIRT_PATH}hack/dockerized "DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} ./hack/build-func-tests.sh"
 ${KUBEVIRT_PATH}hack/dockerized "DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} DOCKER_TAG_ALT=${DOCKER_TAG_ALT} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} IMAGE_PREFIX=${IMAGE_PREFIX} IMAGE_PREFIX_ALT=${IMAGE_PREFIX_ALT} ./hack/bazel-push-images.sh"
-${KUBEVIRT_PATH}hack/dockerized "DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} IMAGE_PULL_POLICY=${IMAGE_PULL_POLICY} VERBOSITY=${VERBOSITY} IMAGE_PREFIX=${IMAGE_PREFIX}  IMAGE_PREFIX_ALT=${IMAGE_PREFIX_ALT} feature_gates=${FEATURE_GATES} ./hack/build-manifests.sh"
+${KUBEVIRT_PATH}hack/dockerized "DOCKER_PREFIX=${DOCKER_PREFIX} DOCKER_TAG=${DOCKER_TAG} KUBEVIRT_PROVIDER=${KUBEVIRT_PROVIDER} IMAGE_PULL_POLICY=${IMAGE_PULL_POLICY} VERBOSITY=${VERBOSITY} IMAGE_PREFIX=${IMAGE_PREFIX}  IMAGE_PREFIX_ALT=${IMAGE_PREFIX_ALT} feature_gates=${FEATURE_GATES} KUBEVIRT_ONLY_USE_TAGS=${KUBEVIRT_ONLY_USE_TAGS} ./hack/build-manifests.sh"
 
 # Make sure that all nodes use the newest images
 container=""
diff --git a/hack/parse-shasums.sh b/hack/parse-shasums.sh
index c53c7484830b..42bd722b3a88 100755
--- a/hack/parse-shasums.sh
+++ b/hack/parse-shasums.sh
@@ -24,6 +24,11 @@ if [[ ! -f "${KUBEVIRT_DIR}/bazel-bin/push-virt-operator.digest" ]]; then
     return
 fi
 
+if [[ ${KUBEVIRT_ONLY_USE_TAGS} == "true" ]]; then
+    echo "found KUBEVIRT_ONLY_USE_TAGS; using tags instead of shasums"
+    return
+fi
+
 # bazel push images creates digest files in bazel-bin/push-<image-name>.digest
 
 VIRT_OPERATOR_SHA=$(cat ${KUBEVIRT_DIR}/bazel-bin/push-virt-operator.digest)

From e24d82817d42b3644be365aeeea4597567ca776b Mon Sep 17 00:00:00 2001
From: Kevin Wiesmueller <kwiesmul@redhat.com>
Date: Tue, 18 May 2021 20:20:38 +0200
Subject: [PATCH 2/2] explain tag based pulls in README.md

Signed-off-by: Kevin Wiesmueller <kwiesmul@redhat.com>
---
 docs/getting-started.md | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/docs/getting-started.md b/docs/getting-started.md
index 19b2f6679c9a..cd8a353c4c32 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -119,6 +119,29 @@ make cluster-down
 **Note:** Whenever you type `make cluster-down && make cluster-up`, you will
 have a completely fresh cluster to play with.
 
+#### Sync specific components
+
+**Note:** The following is meant for allowing faster iteration on small changes to components that support it.
+Not every component is that simply exchangable without a full re-deploy. Always test with the final SHA based method in the end.
+
+In situations where you just want to work on a single component and rollout updates
+without re-deploying the whole environment, you can tell kubevirt to deploy using tags.
+
+```sh
+export KUBEVIRT_ONLY_USE_TAGS=true
+```
+
+After this any `make cluster-sync` will use the `DOCKER_TAG` for pulling images instead of SHAs.
+This means you can simply rebuild the component that changed and then kill the respective pods to
+cause a fresh pull:
+
+```sh
+PUSH_TARGETS='virt-api' ./hack/bazel-push-images.sh
+kubectl delete po -n kubevirt -l kubevirt.io=virt-api
+```
+
+Once the respective component is back, it should be using your new build.
+
 ### Accessing the containerized nodes via ssh
 
 Based on the used cluster, node names might be different.