{"id":1155,"date":"2021-07-27T00:38:27","date_gmt":"2021-07-27T00:38:27","guid":{"rendered":"http:\/\/tiemensfamily.com\/timoncs\/?p=1155"},"modified":"2021-08-01T03:29:59","modified_gmt":"2021-08-01T03:29:59","slug":"kubernetes-and-buildah-and-microk8s","status":"publish","type":"post","link":"https:\/\/tiemensfamily.com\/timoncs\/2021\/07\/27\/kubernetes-and-buildah-and-microk8s\/","title":{"rendered":"Kubernetes and Buildah and microk8s"},"content":{"rendered":"\n

Kubernetes is awesome. But it is very annoying to be halfway through a guide just to have that guide “drop into” docker. Kubernetes _can_ use docker, but it doesn’t _need_ docker. In particular, this is true of microk8s<\/a>. If you have your kubernetes cluster because of microk8s, you won’t have docker installed.<\/p>\n\n\n\n

As an alternative to “docker build”, you can use buildah<\/a> – “a tool that builds Open Container Initiative (OCI) container images”. All that needs done is (1) translate those “docker xxx” commands to buildah, and (2) navigate the registries so that your buildah-built image ends up somewhere that your kubectl can use it.<\/p>\n\n\n\nDockerfile – original<\/b>\n

FROM openjdk:11-jre-slim\nWORKDIR \/app\nCOPY target\/java-hello-world-0.0.1.jar java-hello-world.jar\nENTRYPOINT [\"java\", \"-jar\", \"\/app\/java-hello-world.jar\"]\nEXPOSE 8080<\/code><\/pre>\n\n\n\n
(Gads – a little side note here: WordPress by default allows .doc file types, but denies .txt file types “for security reasons”.  It brings into doubt WordPress’s concept of ‘security’. )<\/p>\n\n\n\n
Note: there are two machines here:  “bld$” is the prompt of the buildah machine.  “k8s$” is the prompt of the microk8s kubernetes machine.<\/p>\n\n\n\n
0. Diversion – create the target\/java-hello-world-0.0.1.jar file by installing java, cloning source from github.  You can skip this step if you already have a java .jar file.<\/p>\n\n\n\nDiversion: install java, create java-hello-world-0.0.1.jar<\/b>\n
bld$ sudo apt install openjdk-11-jdk-headless\nbld$ git clone https:\/\/github.com\/bmuschko\/ckad-study-guide.git\nbld$ cd ckad-study-guide\/ch02\/containerized-java-app\nbld$ .\/mvnw  package spring-boot:repackage\n...snip...\nbld$ ls -hl target\/java-hello-world-0.0.1.jar\n-rw-rw-r-- 17M Jun  8 23:53 target\/java-hello-world-0.0.1.jar\n<\/code><\/pre>\n\n\n\n
1. Install buildah, fix the Dockerfile, and create the container image.<\/p>\n\n\n\nCommand: install buildah and java<\/b>\n
bld$ sudo apt-get -y install buildah<\/code><\/pre>\n\n\n\nDockerfile – fixed for buildah<\/b>\n
FROM docker.io\/openjdk:11-jre-slim\nWORKDIR \/app\nCOPY target\/java-hello-world-0.0.1.jar java-hello-world.jar\nENTRYPOINT [\"java\", \"-jar\", \"\/app\/java-hello-world.jar\"]\nEXPOSE 8080<\/code><\/pre>\n\n\n\nCommand: build with buildah<\/b>\n
bld$ buildah bud -t java-hello-world:1.0.0 . \n\n-- NOTE: \"buildah images\" is the correct command to list images\nbld$ buildah images\nREPOSITORY                    TAG           IMAGE ID       CREATED          SIZE\nlocalhost\/java-hello-world    1.0.0         a24b49859451   7 weeks ago      241 MB\n\n-- Note: \"buildah list\" == \"buildah containers\" == not the correct command\n--       at this step in the process.  kept here only for historical purposes.\nbld$ buildah list\nCONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME\n39d1427e4dad     *     a24b49859451 localhost\/java-hello-world:1.0.0 java-hello-world-working-container<\/code><\/pre>\n\n\n\n
At this time, you have a OCI container image.<\/p>\n\n\n\n