william-yeh / kaniko-demo

Demonstrate how Kaniko makes use of build cache

Kaniko demo

This repo is to demonstrate how Kaniko makes use of build cache.

Build images with Docker CLI

1. Initial build:

   % docker build  -t todoapi:1  src 
   

2. Build again with cache:

   % docker build  -t todoapi:2  src 
   

3. Modify src and re-build with cache:

   % touch src/empty-3
   
   % docker build  -t todoapi:3  src 
   

Result:

Step	Time
1	3m19s
2	0m5.81s
3	0m15.85s

Build images with Kaniko

1. Set environment variable PROJECT_ID and REPO for convenience:

   % export PROJECT_ID=project_id_of_your_gcp_project
   
   % export REPO=repo_name_of_your_image
   

2. Initial build with empty cache:

   % time \
     docker run --rm  -v $(pwd)/src:/kaniko-workspace  \
     gcr.io/kaniko-project/executor:latest             \
         --cache=true  --context=/kaniko-workspace     \
         --destination=gcr.io/$PROJECT_ID/$REPO
   

3. Build again with cache:

   % time \
     docker run --rm  -v $(pwd)/src:/kaniko-workspace  \
     gcr.io/kaniko-project/executor:latest             \
         --cache=true  --context=/kaniko-workspace     \
         --destination=gcr.io/$PROJECT_ID/$REPO
   

4. Modify src and re-build with cache:

   % touch src/empty-4
   
   % time \
     docker run --rm  -v $(pwd)/src:/kaniko-workspace  \
     gcr.io/kaniko-project/executor:latest             \
         --cache=true  --context=/kaniko-workspace     \
         --destination=gcr.io/$PROJECT_ID/$REPO
   

Result:

Step	Time
2	4m23s
3	1m20s
4	1m55s

Caveat with Kaniko + .NET Core SDK

If you use dotnet/core/sdk as base image, you may encounter error messages near the end of Kaniko build steps, similar to the following:

error building image: error building stage: Unable to add file /tmp/clr-debug-pipe-149-16587078-out to layered map: Error creating hash for /tmp/clr-debug-pipe-149-16587078-out: lstat /tmp/clr-debug-pipe-149-16587078-out: no such file or directory

A workaround is to set environment variable COMPlus_EnableDiagnostics before dotnet publish in Dockerfile:

ENV COMPlus_EnableDiagnostics=0
...
dotnet publish

For more info, see GoogleContainerTools/kaniko#391 (comment)

About the TodoApi source code

The sample code in src directory was extracted from the TodoApi demo in the Microsoft Docs site, retrieved on Nov 27, 2019:

• Document - Tutorial: Create a web API with ASP.NET Core MVC

• Source code - https://github.com/aspnet/AspNetCore.Docs/tree/master/aspnetcore/tutorials/first-web-api/samples/3.0/TodoApi

The original source code to be used in this repo is packed in the TodoApi-original.zip file for your reference.