GHA job stuck on Docker build - just started recently

Hello,

I have been having an issue since Sep 23 on one of GHA jobs that were running fine prior to that date.

So, I create a simple GHA job which only build a Docker file. But for some reason, it’s timed out and never completed.

I am using self-hosted runners, and this is the GHA job: (GHA, Current runner version: ‘2.283.1’)

name: debugging-actions

on:
  push:
    branches:
      - debugging-github-actions

jobs:
  build:
    runs-on: [tools-low]
    steps:
      - uses: actions/checkout@v2
      - name: Docker build
        run: docker build .

Dockerfile

FROM alpine:latest
ENV KUBE_LATEST_VERSION="v1.19.9"

RUN apk add --no-cache bash bind-tools jq

RUN apk add --update ca-certificates \
  && apk add --update -t deps curl \
  && export ARCH="$(uname -m)" && if [[ ${ARCH} == "x86_64" ]]; then export ARCH="amd64"; fi && curl -L https://storage.googleapis.com/kubernetes-release/release/${KUBE_LATEST_VERSION}/bin/linux/${ARCH}/kubectl -o /usr/local/bin/kubectl \
  && chmod +x /usr/local/bin/kubectl \
  && apk del --purge deps \
  && rm /var/cache/apk/*

I think this is the answer

It seems like fastly is filtering ICMP need to frag packets, which means that PMTU does not work. This can be a problem is your traffic goes via a network link that has MTU lower than 1500 (typically tunnels/vpns, PPPoE and similar). This can be worked around by enabling tcp mss clamping in the network.