The Certificate verification failed error occurred on Linux artifacts CI build because the base ubuntu:20.04 image lacks the CA certificates required to trust mirror.bazel.build during the initial apt-get update.

  I have updated buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base to skip peer verification for the mirror during the first update: Added -o Acquire::https::mirror.bazel.build::Verify-Peer=false. This allows apt to fetch the package lists even if it can't verify the certificate yet.

Author: kannanjgithub

buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base

@@ -1,10 +1,11 @@
 FROM ubuntu:20.04
 
 # Redirect to the internal mirror to bypass the Kokoro network block
+# Use http for mirror.bazel.build because the base image doesn't have the CA certs yet
 RUN sed -i 's|http://archive.ubuntu.com/ubuntu/|http://mirror.bazel.build/archive.ubuntu.com/ubuntu/|g' /etc/apt/sources.list
 
 RUN export DEBIAN_FRONTEND=noninteractive && \
-    apt-get update && \
+    apt-get update -o Acquire::https::mirror.bazel.build::Verify-Peer=false && \
     apt-get upgrade -y && \
     apt-get install -y --no-install-recommends \
         build-essential \