Reproducible builds: convert instruction to the template

^Relates to KTI-1222

docs/building/index.md

@@ -1,7 +1,74 @@
 # Kotlin builds
 
+This tutorial explains how to build any release starting with 1.9.0-Beta locally.
+
+For earlier releases follow the corresponding instruction:
 * [1.8.20](build-1.8.20.md)
 * [1.8.0](build-1.8.0.md)
 * [1.8.0-Beta](build-1.8.0-Beta.md)
 * [1.7.21](build-1.7.21.md)
 * [1.7.20](build-1.7.20.md)
+
+## Prerequisites
+
+You must have:
+* Linux or macOS.
+* Docker installed.
+* 14 GB memory available and configured in Docker.
+* To get reproducible artifacts, [umask](https://en.wikipedia.org/wiki/Umask) command without parameters should
+  produce `0022` or `022` output.
+
+## Set environment variables
+
+All artifacts are available at the [Kotlin GitHub release page](https://github.com/JetBrains/kotlin/releases)
+
+Each `kotlin-compiler-[DEPLOY_VERSION].zip` artifact contains `build.txt` file with the `BUILD_NUMBER` value
+
+The following environment variables must be set:
+
+```shell
+export DEPLOY_VERSION=*
+export BUILD_NUMBER=*
+export MAVEN_BUILD_NUMBER=BUILD_NUMBER
+export KOTLIN_NATIVE_VERSION=DEPLOY_VERSION
+export DOCKER_CONTAINER_URL=kotlin.registry.jetbrains.space/p/kotlin/containers/kotlin-build-env:v6
+```
+
+## Clone Kotlin repository
+
+In a new folder, clone the release tag from the Kotlin repository, and change directory to the build folder:
+
+```shell
+git clone --depth 1 --branch v$DEPLOY_VERSION https://github.com/JetBrains/kotlin.git kotlin-build-$DEPLOY_VERSION
+cd kotlin-build-$DEPLOY_VERSION
+```
+
+## Build and verify the compiler
+
+```shell
+docker run --rm -it --name kotlin-build-$DEPLOY_VERSION \
+  --workdir="/repo" \
+  --volume="$(pwd):/repo" \
+  --user="$(id -u):$(id -g)" \
+  $DOCKER_CONTAINER_URL \
+  /bin/bash -c "./scripts/build-kotlin-compiler.sh $DEPLOY_VERSION $BUILD_NUMBER"
+```
+
+This generates a ZIP file: `dist/kotlin-compiler-$DEPLOY_VERSION.zip`.
+
+Check that the SHA 256 checksum is equal to the published one for `kotlin-compiler.zip`
+
+## Build and verify maven artifacts
+
+```shell
+docker run --rm -it --name kotlin-build-$DEPLOY_VERSION \
+  --workdir="/repo" \
+  --volume="$(pwd):/repo" \
+  --user="$(id -u):$(id -g)" \
+  $DOCKER_CONTAINER_URL \
+  /bin/bash -c "./scripts/build-kotlin-maven.sh $DEPLOY_VERSION '$MAVEN_BUILD_NUMBER' $KOTLIN_NATIVE_VERSION"
+```
+
+This generates a ZIP file: `build/repo-reproducible/reproducible-maven-$DEPLOY_VERSION.zip`.
+
+Check that the SHA 256 checksum is equal to the checksum, defined in `maven-$DEPLOY_VERSION-sha256.txt`