Merge pull request #3153 from kolyshkin/cirrus-robust

.cirrus.yml: simplify for centos, retry yum

.cirrus.yml

@@ -85,7 +85,6 @@ task:
     memory: 8G
 
   install_dependencies_script: |
-    yum install -y -q epel-release
     case $DISTRO in
     centos-7)
       (cd /etc/yum.repos.d && curl -O https://copr.fedorainfracloud.org/coprs/adrian/criu-el7/repo/epel-7/adrian-criu-el7-epel-7.repo)
@@ -94,11 +93,15 @@ task:
       sysctl --system
       ;;
     centos-stream-8)
-      yum install -y -q dnf-plugins-core
-      yum config-manager --set-enabled powertools
+      yum config-manager --set-enabled powertools # for glibc-static
       ;;
     esac
-    yum install -y -q gcc git iptables jq glibc-static libseccomp-devel make criu
+    # Work around dnf mirror failures by retrying a few times.
+    for i in $(seq 0 2); do
+      sleep $i
+      yum install -y -q gcc git iptables jq glibc-static libseccomp-devel make criu && break
+    done
+    [ $? -eq 0 ] # fail if yum failed
     # install Go
     curl -fsSL "https://dl.google.com/go/go${GO_VERSION}.linux-amd64.tar.gz" | tar Cxz /usr/local
     # install bats