Start with a very simple app that writes a line to stdout every few seconds. When this app is deployed in a Kubernetes pod, you will be able to see this output as the pod's log output.
package main
import (
"fmt"
"time"
)
func main() {
for {
fmt.Println("hello")
time.Sleep(5*time.Second)
}
}
Multistage build Dockerfile
# First stage: start with a Golang base image FROM golang:1.12-alpine3.10 # Move to the directory where the source code will live WORKDIR /go/src/hello # Copy the source code into the current directory COPY hello.go . # Get any dependencies, and compile the code RUN CGO_ENABLED=0 go get -v ./... # Second stage: start from an empty base image FROM scratch # Copy the binary from the first stage COPY --from=0 /go/bin/hello / # Tell Docker what executable to run by default when starting this container ENTRYPOINT ["/hello"]
Build this image and check that it works.
docker build -t hello .
docker run -t hello
This should log output to the screen on a regular basis.
Stop this container from a second terminal.
docker stop $(docker ps --filter ancestor=hello -q)
- See the Docker documentation for more information about filtering the results from
docker ps - The
-qparameter returns just the container ID, which can then be passed to thedocker stopcommand.
Next step
We have a very simple application that we can run in a container. Now let's get Skaffold to run it under Kubernetes.
