Can't connect to Docker container of Spring Boot application using `docker exec`

Question

Reproducer

After start the project, I can't connect to the container using docker exec -it sb-repro [bash | sh]. The error:

OCI runtime exec failed: exec failed: unable to start container process: exec: "bash": executable file not found in $PATH: unknown

Is any shell available? Or is it needed to explicitly add some buildpack here?

Answer 1

To build your container image, you used this specific buildpack:

buildpacks.set(listOf("gcr.io/paketo-buildpacks/java-native-image"))

and you also used the GraalVM Native build tool:

id("org.graalvm.buildtools.native")

If you look at the Gradle Spring Boot plugin documentation, you'll notice that using the build tool makes the plugin use paketobuildpacks/builder-jammy-tiny:latest instead of paketobuildpacks/builder-jammy-base:latest :

paketobuildpacks/builder-jammy-base:latest or paketobuildpacks/builder-jammy-tiny:latest when GraalVM Native Image plugin is applied.

And to make the image size smaller, the tiny variant does not embed common Unix tools such as bash nor sh - which makes the built images even more secure (smaller attack surface) - but less debugable too...

I suggest you debug using the paketobuildpacks/builder-jammy-base:latest base image, run your build with

./gradlew --builder paketobuildpacks/builder-jammy-base:latest bootBuildImage

or updating your build.gradle.kts with:

tasks.withType<BootBuildImage> {
    builder.set("paketobuildpacks/builder-jammy-base:latest")
    ...
}