In building a docker image for a Go application using the Apline image, I kept getting this error “tls: failed to verify certificate: x509: certificate signed by unknown authority”. I thought it was something with the code I was writing, but it had to do with the docker image.
Adding this to your Dockerfile should fix the problem. The problem is that the docker container doesn’t have the necessary certs to validate the connection. You might also get around this issue by adding the “ca-certificates” package to the image, but I didn’t try that.
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
or (depends on how your building your image)
COPY /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/