HADOOP-19222. Switch yum repo baseurl due to CentOS 7 sunset (#6932) Contributed by Cheng Pan.

Reviewed-by: Gautham Banasandra <gaurava@apache.org>
Signed-off-by:  Shilun Fan <slfan1989@apache.org>

dev-support/docker/Dockerfile_centos_7

@@ -30,6 +30,13 @@ COPY pkg-resolver pkg-resolver
 RUN chmod a+x pkg-resolver/*.sh pkg-resolver/*.py \
     && chmod a+r pkg-resolver/*.json
 
+######
+# Centos 7 has reached its EOL and the packages
+# are no longer available on mirror.centos.org site.
+# Please see https://www.centos.org/centos-linux-eol/
+######
+RUN pkg-resolver/set-vault-as-baseurl-centos.sh centos:7
+
 ######
 # Install packages from yum
 ######
@@ -38,8 +45,13 @@ RUN yum update -y \
     && yum groupinstall -y "Development Tools" \
     && yum install -y \
         centos-release-scl \
-        python3 \
-    && yum install -y $(pkg-resolver/resolve.py centos:7)
+        python3
+
+# Apply the script again because centos-release-scl creates new YUM repo files
+RUN pkg-resolver/set-vault-as-baseurl-centos.sh centos:7
+
+# hadolint ignore=DL3008,SC2046
+RUN yum install -y $(pkg-resolver/resolve.py centos:7)
 
 # Set GCC 9 as the default C/C++ compiler
 RUN echo "source /opt/rh/devtoolset-9/enable" >> /etc/bashrc

dev-support/docker/pkg-resolver/set-vault-as-baseurl-centos.sh

@@ -24,7 +24,7 @@ fi
 if [ "$1" == "centos:7" ] || [ "$1" == "centos:8" ]; then
   cd /etc/yum.repos.d/ || exit &&
     sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-* &&
-    sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-* &&
+    sed -i 's|# *baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-* &&
     yum update -y &&
     cd /root || exit
 else