title: No package nginx available after install epel in CentOS 7.9
body: <p>I am using this command to install epel-relsease:</p>
  <pre><code>[root@izbp19pke6x0v6ruecuy1yz ~]# yum install epel-release
  Loaded plugins: elrepo, fastestmirror, product-id, search-disabled-repos, subscription-
                : manager
  
  This system is not registered with an entitlement server. You can use subscription-manager to register.
  
  Repository base is listed more than once in the configuration
  Repository updates is listed more than once in the configuration
  Repository extras is listed more than once in the configuration
  Repository centosplus is listed more than once in the configuration
  Loading mirror speeds from cached hostfile
   * base: mirrors.163.com
   * centos-sclo-rh: mirrors.163.com
   * centos-sclo-sclo: mirrors.163.com
   * elrepo: hkg.mirror.rackspace.com
   * extras: mirrors.163.com
   * remi-safe: mirror.innosol.asia
   * updates: mirrors.163.com
  [elrepo]: excluding package: kmod-3c59x-0.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-8188eu-5.2.2.4-2.20190907git.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-a3818-1.6.2-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-aic7xxx-7.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-ar5523-0.0-10.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-ath5k-0.0-13.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-cassini-1.6-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-cciss-3.6.26-7.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-cciss-3.6.26-8.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-drbd84-8.4.11-1.2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-drbd90-9.0.22-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-e100-3.5.24-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-e1000e-3.8.4-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-e1000e-3.8.4-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-ecryptfs-0.1-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-forcedeth-0.64-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-fpga-mgr-0.0-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-hfs-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-hfsplus-0.0-5.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-i2c-i801-0.0-6.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgb-1.0.135-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgbe-5.6.3-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgbe-5.6.3-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-joydev-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-mac802154_hwsim-0.0-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-mbgclock-4.2.10-1.el7.elrepo.x86_64
  [elrepo]: excluding package: kmod-mt7601u-4.14.108-3.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nct6775-0.0-5.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-ne2k-pci-1.03-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-netatop-0.3-4.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-netatop-2.0-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-niu-1.1-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.64-1.el7_7.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.82-1.el7_8.elrepo.i686
  [elrepo]: excluding package: kmod-nvidia-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.100-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.57-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.66-1.el7_8.elrepo.i686
  [elrepo]: excluding package: kmod-nvidia-340xx-340.107-3.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-390xx-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.116-2.el7_7.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-390xx-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-390xx-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.138-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8125-9.003.05-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8168-8.047.05-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8168-8.048.00-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8169-6.020.00-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-reiserfs-0.0-3.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-rr62x-1.2-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-rr64xl-1.4.0-1.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-rtl8812au-5.3.4-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-sis190-1.4-1.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-sis900-1.08.10-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-sym53c8xx-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-tpe-2.0.4-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-typhoon-1.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-usbip-1.0.1-4.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-via-rhine-1.5.1-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-via-velocity-1.15-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200611-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200623-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200712-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: 8:kmod-wireguard-1.0.20200729-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: 8:kmod-wireguard-1.0.20200908-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-xpad-0.0.6-9.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-zd1211rw-1.0-8.el7_8.elrepo.x86_64
  Package matching epel-release-7-11.noarch already installed. Checking for update.
  Nothing to do
  </code></pre>
  <p>then using this command to install nginx:</p>
  <pre><code>[root@izbp19pke6x0v6ruecuy1yz ~]# yum install nginx
  Loaded plugins: elrepo, fastestmirror, product-id, search-disabled-repos, subscription-
                : manager
  
  This system is not registered with an entitlement server. You can use subscription-manager to register.
  
  Repository base is listed more than once in the configuration
  Repository updates is listed more than once in the configuration
  Repository extras is listed more than once in the configuration
  Repository centosplus is listed more than once in the configuration
  Loading mirror speeds from cached hostfile
   * base: mirrors.163.com
   * centos-sclo-rh: mirrors.163.com
   * centos-sclo-sclo: mirrors.163.com
   * elrepo: hkg.mirror.rackspace.com
   * extras: mirrors.163.com
   * remi-safe: mirror.innosol.asia
   * updates: mirrors.163.com
  [elrepo]: excluding package: kmod-3c59x-0.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-8188eu-5.2.2.4-2.20190907git.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-a3818-1.6.2-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-aic7xxx-7.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-ar5523-0.0-10.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-ath5k-0.0-13.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-cassini-1.6-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-cciss-3.6.26-7.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-cciss-3.6.26-8.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-drbd84-8.4.11-1.2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-drbd90-9.0.22-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-e100-3.5.24-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-e1000e-3.8.4-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-e1000e-3.8.4-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-ecryptfs-0.1-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-forcedeth-0.64-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-fpga-mgr-0.0-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-hfs-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-hfsplus-0.0-5.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-i2c-i801-0.0-6.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgb-1.0.135-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgbe-5.6.3-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-ixgbe-5.6.3-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-joydev-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-mac802154_hwsim-0.0-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-mbgclock-4.2.10-1.el7.elrepo.x86_64
  [elrepo]: excluding package: kmod-mt7601u-4.14.108-3.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nct6775-0.0-5.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-ne2k-pci-1.03-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-netatop-0.3-4.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-netatop-2.0-1.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-niu-1.1-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.64-1.el7_7.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-440.64-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-440.82-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.82-1.el7_8.elrepo.i686
  [elrepo]: excluding package: kmod-nvidia-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.100-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-440.100-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.57-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-450.57-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.66-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-libs-450.66-1.el7_8.elrepo.i686
  [elrepo]: excluding package: kmod-nvidia-340xx-340.107-3.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-390xx-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.116-2.el7_7.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-390xx-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.116-2.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-nvidia-390xx-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.138-1.el7_8.elrepo.i686
  [elrepo]: excluding package: nvidia-x11-drv-390xx-libs-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: nvidia-x11-drv-390xx-390.138-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8125-9.003.05-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8168-8.047.05-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8168-8.048.00-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-r8169-6.020.00-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-reiserfs-0.0-3.el7_6.elrepo.x86_64
  [elrepo]: excluding package: kmod-rr62x-1.2-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-rr64xl-1.4.0-1.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-rtl8812au-5.3.4-2.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-sis190-1.4-1.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-sis900-1.08.10-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-sym53c8xx-0.0-4.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-tpe-2.0.4-1.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-typhoon-1.0-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-usbip-1.0.1-4.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-via-rhine-1.5.1-3.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-via-velocity-1.15-2.el7_5.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200611-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200623-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-wireguard-1.0.20200712-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: 8:kmod-wireguard-1.0.20200729-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: 8:kmod-wireguard-1.0.20200908-1.el7_8.elrepo.x86_64
  [elrepo]: excluding package: kmod-xpad-0.0.6-9.el7_7.elrepo.x86_64
  [elrepo]: excluding package: kmod-zd1211rw-1.0-8.el7_8.elrepo.x86_64
  No package nginx available.
  Error: Nothing to do
  </code></pre>
  <p>what should I do to install nginx? this is the system version info:</p>
  <pre><code>[root@izbp19pke6x0v6ruecuy1yz ~]#  lsb_release -a
  LSB Version:    :core-4.1-amd64:core-4.1-noarch
  Distributor ID: CentOS
  Description:    CentOS Linux release 7.9.2009 (Core)
  Release:    7.9.2009
  Codename:   Core
  </code></pre>