报错信息：
[root@localhost backup]# yum -y install net-snmpLoaded plugins: fastestmirrorRepository base is listed more than once in the configurationRepository addons is listed more than once in the configurationRepository extras is listed more than once in the configurationRepository centosplus is listed more than once in the configurationRepository contrib is listed more than once in the configurationLoading mirror speeds from cached hostfile* updates: centos.Setting up Install ProcessResolving Dependencies--> Running transaction check---> Package net-snmp.x86_64 1:5.3.2.2-9.el5_5.1 set to be updated--> Processing Dependency: net-snmp-libs = 1:5.3.2.2-9.el5_5.1 for package: net-snmp--> Processing Dependency: libsensors.so.3()(64bit) for package: net-snmp--> Running transaction check---> Package lm_sensors.x86_64 0:2.10.7-9.el5 set to be updated---> Package net-snmp-libs.i386 1:5.3.2.2-9.el5_5.1 set to be updated---> Package net-snmp-libs.x86_64 1:5.3.2.2-9.el5_5.1 set to be updated--> Finished Dependency ResolutionDependencies Resolved===================================================================================================================================================Package Arch Version Repository Size===================================================================================================================================================Installing:net-snmp x86_64 1:5.3.2.2-9.el5_5.1 update 702 kInstalling for dependencies:lm_sensors x86_64 2.10.7-9.el5 base 525 kUpdating for dependencies:net-snmp-libs i386 1:5.3.2.2-9.el5_5.1 update 1.3 Mnet-snmp-libs x86_64 1:5.3.2.2-9.el5_5.1 update 1.3 MTransaction Summary===================================================================================================================================================Install 2 Package(s)Upgrade 2 Package(s)Total size: 3.7 MDownloading Packages:warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID e8562897update/gpgkey | 1.8 kB 00:00Public key for net-snmp-libs-5.3.2.2-9.el5_5.1.x86_64.rpm is not installed
在网上解决方法：
此时要导入rpm的签名信息即可
以root登录，执行下面命令
# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
Linux版本是CentOS 7.4
执行下面命令
#rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
