Remove CentOS image

CentOS has been dismissed and not supported anymore.

Change-Id: I2297148dbb3c5b409e617e3401c1e0d54e4bcd4e
diff --git a/README.md b/README.md
index dd72e68..08fb11e 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,7 @@
 git checkout v3.3.0
 ```
 
-Navigate to either `./centos/8` or `./ubuntu/20` to build the centos- or ubuntu-based docker image,
+Navigate to either `./almalinux/8` or `./ubuntu/20` to build the almalinux- or ubuntu-based docker image,
 respectively. Then run:
 
 ```
diff --git a/centos/8/.dockerignore b/centos/8/.dockerignore
deleted file mode 100644
index a8c4f8a..0000000
--- a/centos/8/.dockerignore
+++ /dev/null
@@ -1 +0,0 @@
-/var/gerrit/.gerritcodereview
diff --git a/centos/8/Dockerfile b/centos/8/Dockerfile
deleted file mode 100644
index 63956e8..0000000
--- a/centos/8/Dockerfile
+++ /dev/null
@@ -1,31 +0,0 @@
-FROM centos:8.2.2004
-MAINTAINER Gerrit Code Review Community
-
-# Add Gerrit packages repository
-RUN rpm -i https://gerritforge.com/gerritforge-repo-1-2.noarch.rpm
-
-ADD entrypoint.sh /
-
-# Install OS pre-prequisites, OpenJDK and Gerrit in two subsequent transactions
-# (pre-trans Gerrit script needs to have access to the Java command)
-RUN yum -y install initscripts && \
-    yum -y install java-11-openjdk && \
-    yum -y install gerrit-3.5.0.1-1 && \
-    /entrypoint.sh init && \
-    rm -f /var/gerrit/etc/{ssh,secure}* && rm -Rf /var/gerrit/{static,index,logs,data,index,cache,git,db,tmp}/* && chown -R gerrit:gerrit /var/gerrit && \
-    yum -y clean all
-
-# Enable LEGACY security policies by default (for TLS 1.0/1.1 compatibility)
-RUN update-crypto-policies --set LEGACY
-
-USER gerrit
-
-ENV CANONICAL_WEB_URL=
-ENV HTTPD_LISTEN_URL=
-
-# Allow incoming traffic
-EXPOSE 29418 8080
-
-VOLUME ["/var/gerrit/git", "/var/gerrit/index", "/var/gerrit/cache", "/var/gerrit/db", "/var/gerrit/etc"]
-
-ENTRYPOINT ["/entrypoint.sh"]
diff --git a/centos/8/Dockerfile-dev b/centos/8/Dockerfile-dev
deleted file mode 100644
index 38677a1..0000000
--- a/centos/8/Dockerfile-dev
+++ /dev/null
@@ -1,36 +0,0 @@
-FROM centos:8.1.1911
-MAINTAINER Gerrit Code Review Community
-
-ARG GERRIT_WAR_URL="https://gerrit-ci.gerritforge.com/view/Gerrit/job/Gerrit-bazel-master/lastSuccessfulBuild/artifact/gerrit/bazel-bin/release.war"
-
-# Allow remote connectivity and sudo and install OpenJDK and Git
-# (pre-trans Gerrit script needs to have access to the Java command)
-RUN yum -y install \
-    openssh-clients \
-    initscripts \
-    sudo \
-    java-11-openjdk \
-    git && \
-    yum -y clean all
-
-ADD entrypoint.sh /
-
-RUN adduser -m gerrit --home-dir /home/gerrit && \
-    mkdir -p /var/gerrit/bin && \
-    chown -R gerrit /var/gerrit
-USER gerrit
-ADD --chown=gerrit $GERRIT_WAR_URL  /var/gerrit/bin/gerrit.war
-RUN mkdir -p /var/gerrit/etc && \
-    touch /var/gerrit/etc/gerrit.config && \
-    git config -f /var/gerrit/etc/gerrit.config auth.type DEVELOPMENT_BECOME_ANY_ACCOUNT && \
-    git config --add -f /var/gerrit/etc/gerrit.config container.javaOptions "-Djava.security.egd=file:/dev/./urandom"
-
-ENV CANONICAL_WEB_URL=
-ENV HTTPD_LISTEN_URL=
-
-# Allow incoming traffic
-EXPOSE 29418 8080
-
-VOLUME ["/var/gerrit/git", "/var/gerrit/index", "/var/gerrit/cache", "/var/gerrit/db", "/var/gerrit/etc"]
-
-ENTRYPOINT ["/entrypoint.sh"]
diff --git a/centos/8/entrypoint.sh b/centos/8/entrypoint.sh
deleted file mode 100755
index 1fc4530..0000000
--- a/centos/8/entrypoint.sh
+++ /dev/null
@@ -1,25 +0,0 @@
-#!/bin/bash -e
-
-export JAVA_OPTS='--add-opens java.base/java.net=ALL-UNNAMED --add-opens java.base/java.lang.invoke=ALL-UNNAMED'
-
-if [ ! -d /var/gerrit/git/All-Projects.git ] || [ "$1" == "init" ]
-then
-  echo "Initializing Gerrit site ..."
-  java $JAVA_OPTS -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit
-  java $JAVA_OPTS -jar /var/gerrit/bin/gerrit.war reindex -d /var/gerrit
-  git config -f /var/gerrit/etc/gerrit.config --add container.javaOptions "-Djava.security.egd=file:/dev/./urandom"
-  git config -f /var/gerrit/etc/gerrit.config --add container.javaOptions "--add-opens java.base/java.net=ALL-UNNAMED"
-  git config -f /var/gerrit/etc/gerrit.config --add container.javaOptions "--add-opens java.base/java.lang.invoke=ALL-UNNAMED"
-fi
-
-git config -f /var/gerrit/etc/gerrit.config gerrit.canonicalWebUrl "${CANONICAL_WEB_URL:-http://$HOSTNAME}"
-if [ ${HTTPD_LISTEN_URL} ];
-then
-  git config -f /var/gerrit/etc/gerrit.config httpd.listenUrl ${HTTPD_LISTEN_URL}
-fi
-
-if [ "$1" != "init" ]
-then
-  echo "Running Gerrit ..."
-  exec /var/gerrit/bin/gerrit.sh run
-fi