diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 01c7d03..d926572 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,6 +11,13 @@ on:
       - fix/**
       - pr/**
 
+concurrency:
+  group: ${{format('{0}:{1}', github.repository, github.ref)}}
+  cancel-in-progress: true
+
+env:
+  NET_RETRY_COUNT: 5
+
 jobs:
   posix:
     strategy:
@@ -110,7 +117,7 @@ jobs:
             cxxstd: "03,11,14,17"
           - name: "TOOLSET=clang COMPILER=clang++ CXXSTD=03,11 Job 7"
             buildtype: "boost"
-            packages: ""
+            packages: "clang"
             packages_to_remove: ""
             os: "ubuntu-22.04"
             container: "ubuntu:18.04"
@@ -223,13 +230,17 @@ jobs:
       - name: If running in container, upgrade packages
         if: matrix.container != ''
         run: |
-            apt-get -o Acquire::Retries=3 update && DEBIAN_FRONTEND=noninteractive apt-get -y install tzdata && apt-get -o Acquire::Retries=3 install -y sudo software-properties-common wget curl apt-transport-https make apt-file sudo unzip libssl-dev build-essential autotools-dev autoconf automake g++ libc++-helpers python ruby cpio gcc-multilib g++-multilib pkgconf python3 ccache libpython-dev
-            sudo apt-add-repository ppa:git-core/ppa
-            sudo apt-get -o Acquire::Retries=3 update && apt-get -o Acquire::Retries=3 -y install git
-            python_version=$(python3 -c 'import sys; print("{0.major}.{0.minor}".format(sys.version_info))')
-            sudo wget https://bootstrap.pypa.io/pip/$python_version/get-pip.py
-            sudo python3 get-pip.py
-            sudo /usr/local/bin/pip install cmake
+            if [ -f "/etc/debian_version" ]; then
+                echo "DEBIAN_FRONTEND=noninteractive" >> $GITHUB_ENV
+                export DEBIAN_FRONTEND=noninteractive
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y sudo software-properties-common curl wget apt-transport-https ca-certificates
+                # Need (newer) git, and the older Ubuntu container may require requesting the key manually using port 80
+                curl -sSL --retry ${NET_RETRY_COUNT:-5} 'http://keyserver.ubuntu.com/pks/lookup?op=get&search=0xE1DD270288B4E6030699E45FA1715D88E1DF1F24' | sudo gpg --dearmor > /etc/apt/trusted.gpg.d/git-core_ubuntu_ppa.gpg
+                for i in {1..${NET_RETRY_COUNT:-3}}; do sudo -E add-apt-repository -y ppa:git-core/ppa && break || sleep 10; done
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT update
+                apt-get -o Acquire::Retries=$NET_RETRY_COUNT install -y g++ python libpython-dev git unzip libssl-dev build-essential libc++-helpers gcc-multilib g++-multilib pkgconf ccache
+            fi
 
       - uses: actions/checkout@v2