diff --git a/fluent-package/yum/systemd-test/downgrade-to-v4.sh b/fluent-package/yum/systemd-test/downgrade-to-v4.sh
index 1eb382631..297655488 100755
--- a/fluent-package/yum/systemd-test/downgrade-to-v4.sh
+++ b/fluent-package/yum/systemd-test/downgrade-to-v4.sh
@@ -9,6 +9,12 @@ case ${distribution} in
     amazon)
 	curl -fsSL https://toolbelt.treasuredata.com/sh/install-amazon2-td-agent4.sh | sh
 	;;
+    centos)
+	sudo sed -i -e 's,^mirrorlist=,#mirrorlist,' /etc/yum.repos.d/CentOS-Base.repo
+	sudo sed -i -e 's,^#baseurl=http://mirror.centos.org/centos/\$releasever/,baseurl=http://ftp.iij.ad.jp/pub/linux/centos/7.9.2009/,' /etc/yum.repos.d/CentOS-Base.repo
+        cat /etc/yum.repos.d/CentOS-Base.repo
+	curl -fsSL https://toolbelt.treasuredata.com/sh/install-redhat-td-agent4.sh | sh
+	;;
     *)
 	curl -fsSL https://toolbelt.treasuredata.com/sh/install-redhat-td-agent4.sh | sh
 	;;
diff --git a/fluent-package/yum/systemd-test/install-newly.sh b/fluent-package/yum/systemd-test/install-newly.sh
index 46cf8402c..c15c88786 100755
--- a/fluent-package/yum/systemd-test/install-newly.sh
+++ b/fluent-package/yum/systemd-test/install-newly.sh
@@ -4,6 +4,14 @@ set -exu
 
 . $(dirname $0)/commonvar.sh
 
+case $DISTRIBUTION in
+    centos)
+	sudo sed -i -e 's,^mirrorlist=,#mirrorlist,' /etc/yum.repos.d/CentOS-Base.repo
+	sudo sed -i -e 's,^#baseurl=http://mirror.centos.org/centos/\$releasever/,baseurl=http://ftp.iij.ad.jp/pub/linux/centos/7.9.2009/,' /etc/yum.repos.d/CentOS-Base.repo
+        cat /etc/yum.repos.d/CentOS-Base.repo
+	;;
+esac
+
 case $1 in
   local)
     sudo $DNF install -y \
diff --git a/fluent-package/yum/systemd-test/update-from-v4.sh b/fluent-package/yum/systemd-test/update-from-v4.sh
index 1593893e7..09dca4578 100755
--- a/fluent-package/yum/systemd-test/update-from-v4.sh
+++ b/fluent-package/yum/systemd-test/update-from-v4.sh
@@ -17,6 +17,11 @@ gpgkey=https://packages.treasuredata.com/GPG-KEY-td-agent
 EOF
         sudo mv td.repo /etc/yum.repos.d/
         ;;
+    centos)
+	sudo sed -i -e 's,^mirrorlist=,#mirrorlist,' /etc/yum.repos.d/CentOS-Base.repo
+	sudo sed -i -e 's,^#baseurl=http://mirror.centos.org/centos/\$releasever/,baseurl=http://ftp.iij.ad.jp/pub/linux/centos/7.9.2009/,' /etc/yum.repos.d/CentOS-Base.repo
+        cat /etc/yum.repos.d/CentOS-Base.repo
+	;;
     *)
         cat > td.repo <<'EOF';
 [treasuredata]
diff --git a/fluent-package/yum/systemd-test/update-to-next-version-with-backward-compat-for-v4.sh b/fluent-package/yum/systemd-test/update-to-next-version-with-backward-compat-for-v4.sh
index f18dabbb2..4d44ef0a7 100755
--- a/fluent-package/yum/systemd-test/update-to-next-version-with-backward-compat-for-v4.sh
+++ b/fluent-package/yum/systemd-test/update-to-next-version-with-backward-compat-for-v4.sh
@@ -17,6 +17,11 @@ gpgkey=https://packages.treasuredata.com/GPG-KEY-td-agent
 EOF
         sudo mv td.repo /etc/yum.repos.d/
         ;;
+    centos)
+	sudo sed -i -e 's,^mirrorlist=,#mirrorlist,' /etc/yum.repos.d/CentOS-Base.repo
+	sudo sed -i -e 's,^#baseurl=http://mirror.centos.org/centos/\$releasever/,baseurl=http://ftp.iij.ad.jp/pub/linux/centos/7.9.2009/,' /etc/yum.repos.d/CentOS-Base.repo
+        cat /etc/yum.repos.d/CentOS-Base.repo
+	;;
     *)
         cat > td.repo <<'EOF';
 [treasuredata]
diff --git a/fluent-package/yum/systemd-test/update-to-next-version.sh b/fluent-package/yum/systemd-test/update-to-next-version.sh
index 10dd7ce57..70a75872a 100755
--- a/fluent-package/yum/systemd-test/update-to-next-version.sh
+++ b/fluent-package/yum/systemd-test/update-to-next-version.sh
@@ -24,6 +24,13 @@ case $distribution in
 	;;
 	esac
         ;;
+    centos)
+	sudo sed -i -e 's,^mirrorlist=,#mirrorlist,' /etc/yum.repos.d/CentOS-Base.repo
+	sudo sed -i -e 's,^#baseurl=http://mirror.centos.org/centos/\$releasever/,baseurl=http://ftp.iij.ad.jp/pub/linux/centos/7.9.2009/,' /etc/yum.repos.d/CentOS-Base.repo
+        cat /etc/yum.repos.d/CentOS-Base.repo
+        sudo $DNF install -y epel-release
+	sudo $DNF install -y rpmrebuild
+	;;
     *)
         sudo $DNF install -y epel-release
 	sudo $DNF install -y rpmrebuild