话说
各位小伙伴，晚上好。这里终结一下yum仓库更新的方式。之所以总结这个，是因为上一篇在ECS安装MySQL虽然受挫但终究或多或少有点点收获，那就是yum的基本运作原理。这里会按照官网方式介绍yum如何安装MySQL来说明寡人对yum安装的进一步认识。
目录
1、如何更新yum固有的仓库？
2、如何选择yum默认安装的版本？
3、原理总结
1、如何更新yum固有的仓库？
地球人都知道，Yum是在线安装。在线安装的好处就是不用下载包包。坏处呢？坏处就是你得知道你要安装的版本这个yum仓库中有，否则你的yum -y install mysql就默认安装的是仓库中固有的版本。但是我想安装最新版本呢？我怎么查看仓库已有什么版本？
查看yum可以按照的版本
yum list | grep ^mysql如果版本中没有最新的MySQL8.0呢？怎么办？
1）去MySQL官网下载rpm包；
2）上传并执行命令
sudo yum localinstall platform-and-version-specific-package-name.rpm效果如图：
如何查看呢？
[root@izuf6i3jkmikgmou78pwvfz ~]# yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community 51
mysql-tools-community/x86_64 MySQL Tools Community 63
mysql80-community/x86_64 MySQL 8.0 Community Server 17
[root@izuf6i3jkmikgmou78pwvfz ~]#
当然也可以这么查看
[root@izuf6i3jkmikgmou78pwvfz ~]# yum list | grep ^mysql
mysql-community-client.x86_64 8.0.11-1.el7 @mysql80-community
mysql-community-common.x86_64 8.0.11-1.el7 @mysql80-community
mysql-community-libs.x86_64 8.0.11-1.el7 @mysql80-community
mysql-community-libs-compat.x86_64 8.0.11-1.el7 @mysql80-community
mysql-community-server.x86_64 8.0.11-1.el7 @mysql80-community
mysql80-community-release.noarch el7-1 installed
mysql++.x86_64 3.1.0-12.el7 epel
mysql++-devel.x86_64 3.1.0-12.el7 epel
mysql++-manuals.x86_64 3.1.0-12.el7 epel
mysql-community-client.i686 8.0.11-1.el7 mysql80-community
mysql-community-common.i686 8.0.11-1.el7 mysql80-community
mysql-community-devel.i686 8.0.11-1.el7 mysql80-community
mysql-community-devel.x86_64 8.0.11-1.el7 mysql80-community
mysql-community-embedded-compat.i686 8.0.11-1.el7 mysql80-community
mysql-community-embedded-compat.x86_64 8.0.11-1.el7 mysql80-community
mysql-community-libs.i686 8.0.11-1.el7 mysql80-community
mysql-community-libs-compat.i686 8.0.11-1.el7 mysql80-community
mysql-community-release.noarch el7-5 mysql-connectors-community
mysql-community-test.x86_64 8.0.11-1.el7 mysql80-community
mysql-connector-java.noarch 1:5.1.25-3.el7 base
mysql-connector-odbc.x86_64 8.0.11-1.el7 mysql-connectors-community
mysql-connector-odbc-debuginfo.x86_64 8.0.11-1.el7 mysql-connectors-community
mysql-connector-odbc-setup.x86_64 8.0.11-1.el7 mysql-connectors-community
mysql-connector-python.noarch 2.0.4-1.el7 mysql-connectors-community
mysql-connector-python.x86_64 8.0.11-1.el7 mysql-connectors-community
mysql-connector-python-cext.x86_64 8.0.11-1.el7 mysql-connectors-community
mysql-connector-python-debuginfo.x86_64 2.1.7-1.el7 mysql-connectors-community
mysql-mmm.noarch 2.2.1-15.el7 epel
mysql-mmm-agent.noarch 2.2.1-15.el7 epel
mysql-mmm-monitor.noarch 2.2.1-15.el7 epel
mysql-mmm-tools.noarch 2.2.1-15.el7 epel
mysql-proxy.x86_64 0.8.5-2.el7 epel
mysql-proxy-devel.x86_64 0.8.5-2.el7 epel
mysql-ref-manual-8.0-en-html-chapter.noarch
mysql-ref-manual-8.0-en-pdf.noarch 1-20180420 mysql80-community
mysql-router.x86_64 8.0.11-1.el7 mysql-tools-community
mysql-router-debuginfo.x86_64 8.0.11-1.el7 mysql-tools-community
mysql-shell.x86_64 8.0.11-1.el7 mysql-tools-community
mysql-shell-debuginfo.x86_64 8.0.11-1.el7 mysql-tools-community
mysql-utilities.noarch 1.6.5-1.el7 mysql-tools-community
mysql-utilities-extra.noarch 1.5.6-1.el7 mysql-tools-community
mysql-workbench-community.x86_64 6.3.10-1.el7 mysql-tools-community
mysql-workbench-community-debuginfo.x86_64
mysqlreport.noarch 3.5-11.el7 epel
mysqltuner.noarch 1.6.0-1.el7 epel
[root@izuf6i3jkmikgmou78pwvfz ~]#
2、如何选择yum默认安装的版本？
0k!上面表明，yum源里面已经有这个包包了，那么如果执行yum -y install mysql，到底安装的是哪个版本呢？
[root@izuf6i3jkmikgmou78pwvfz ~]# yum repolist all | grep mysql
mysql-cluster-7.5-community/x86_64 MySQL Cluster 7.5 Community 禁用
mysql-cluster-7.5-community-source MySQL Cluster 7.5 Community - So 禁用
mysql-cluster-7.6-community/x86_64 MySQL Cluster 7.6 Community 禁用
mysql-cluster-7.6-community-source MySQL Cluster 7.6 Community - So 禁用
mysql-connectors-community/x86_64 MySQL Connectors Community 启用: 51
mysql-connectors-community-source MySQL Connectors Community - Sou 禁用
mysql-tools-community/x86_64 MySQL Tools Community 启用: 63
mysql-tools-community-source MySQL Tools Community - Source 禁用
mysql-tools-preview/x86_64 MySQL Tools Preview 禁用
mysql-tools-preview-source MySQL Tools Preview - Source 禁用
mysql55-community/x86_64 MySQL 5.5 Community Server 禁用
mysql55-community-source MySQL 5.5 Community Server - Sou 禁用
mysql56-community/x86_64 MySQL 5.6 Community Server 禁用
mysql56-community-source MySQL 5.6 Community Server - Sou 禁用
mysql57-community/x86_64 MySQL 5.7 Community Server 禁用
mysql57-community-source MySQL 5.7 Community Server - Sou 禁用
mysql80-community/x86_64 MySQL 8.0 Community Server 启用: 17
mysql80-community-source MySQL 8.0 Community Server - Sou 禁用
[root@izuf6i3jkmikgmou78pwvfz ~]# yum list all | grep mysql
这个命令可以让我们非常清楚的看清楚默认启用的版本。这个默认启动，就是yum -y install默认安装的版本，当然你可以随心所欲的修改。
问题关键来了，如何修改默认启动版本？
两种方式：
方式一：命令
方式二：配置
核心命令就2个
yum-config-manager --disable mysql80-community
yum-config-manager --enable mysql80-community要想使用yum-config-manager，需要先安装下：yum -y install yum-utils (CentOS 7.5)
[root@izuf6i3jkmikgmou78pwvfz ~]# yum -y install yum-utils
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
软件包 yum-utils-1.1.31-45.el7.noarch 已安装并且是最新版本
无须任何处理然后就是enabled disabled的事情了。
方式一：命令
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]# yum-config-manager --disable mysql80-community
已加载插件：fastestmirror
==================================================== repo: mysql80-community =====================================================
[mysql80-community]
async = True
bandwidth = 0
base_persistdir = /var/lib/yum/repos/x86_64/7
baseurl = http://repo.mysql.com/yum/mysql-8.0-community/el/7/x86_64/
cache = 0
cachedir = /var/cache/yum/x86_64/7/mysql80-community
check_config_file_age = True
compare_providers_priority = 80
cost = 1000
deltarpm_metadata_percentage = 100
deltarpm_percentage =
enabled = 0
enablegroups = True
exclude =
failovermethod = priority
ftp_disable_epsv = False
gpgcadir = /var/lib/yum/repos/x86_64/7/mysql80-community/gpgcadir
gpgcakey =
gpgcheck = True
gpgdir = /var/lib/yum/repos/x86_64/7/mysql80-community/gpgdir
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
hdrdir = /var/cache/yum/x86_64/7/mysql80-community/headers
http_caching = all
includepkgs =
ip_resolve =
keepalive = True
keepcache = False
mddownloadpolicy = sqlite
mdpolicy = group:small
mediaid =
metadata_expire = 21600
metadata_expire_filter = read-only:present
metalink =
minrate = 0
mirrorlist =
mirrorlist_expire = 86400
name = MySQL 8.0 Community Server
old_base_cache_dir =
password =
persistdir = /var/lib/yum/repos/x86_64/7/mysql80-community
pkgdir = /var/cache/yum/x86_64/7/mysql80-community/packages
proxy = False
proxy_dict =
proxy_password =
proxy_username =
repo_gpgcheck = False
retries = 10
skip_if_unavailable = False
ssl_check_cert_permissions = True
sslcacert =
sslclientcert =
sslclientkey =
sslverify = True
throttle = 0
timeout = 30.0
ui_id = mysql80-community/x86_64
ui_repoid_vars = releasever,
basearch
username = 如何恢复呢？
#恢复过来也一样：
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]# yum-config-manager --enable mysql80-community
已加载插件：fastestmirror
==================================================== repo: mysql80-community =====================================================
[mysql80-community]
async = True
bandwidth = 0
base_persistdir = /var/lib/yum/repos/x86_64/7
baseurl = http://repo.mysql.com/yum/mysql-8.0-community/el/7/x86_64/
cache = 0
cachedir = /var/cache/yum/x86_64/7/mysql80-community
check_config_file_age = True
compare_providers_priority = 80
cost = 1000
deltarpm_metadata_percentage = 100
deltarpm_percentage =
enabled = 1
enablegroups = True
exclude =
failovermethod = priority
ftp_disable_epsv = False
gpgcadir = /var/lib/yum/repos/x86_64/7/mysql80-community/gpgcadir
gpgcakey =
gpgcheck = True
gpgdir = /var/lib/yum/repos/x86_64/7/mysql80-community/gpgdir
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
hdrdir = /var/cache/yum/x86_64/7/mysql80-community/headers
http_caching = all
includepkgs =
ip_resolve =
keepalive = True
keepcache = False
mddownloadpolicy = sqlite
mdpolicy = group:small
mediaid =
metadata_expire = 21600
metadata_expire_filter = read-only:present
metalink =
minrate = 0
mirrorlist =
mirrorlist_expire = 86400
name = MySQL 8.0 Community Server
old_base_cache_dir =
password =
persistdir = /var/lib/yum/repos/x86_64/7/mysql80-community
pkgdir = /var/cache/yum/x86_64/7/mysql80-community/packages
proxy = False
proxy_dict =
proxy_password =
proxy_username =
repo_gpgcheck = False
retries = 10
skip_if_unavailable = False
ssl_check_cert_permissions = True
sslcacert =
sslclientcert =
sslclientkey =
sslverify = True
throttle = 0
timeout = 30.0
ui_id = mysql80-community/x86_64
ui_repoid_vars = releasever,
basearch
username =
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]#
方式二：配置
上面每个命令对应的都是修改配置文件。
Besides using yum-config-manager or the dnf config-manager command, you can also select a release series by editing manually the/etc/yum.repos.d/mysql-community.repo file. This is a typical entry for a release series’ subrepository in the file:
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]# pwd
/etc/yum.repos.d
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]# ls -l
总用量 16
-rw-r–r– 1 root root 675 5月 30 11:47 CentOS-Base.repo
-rw-r–r– 1 root root 230 5月 30 11:47 epel.repo
-rw-r–r– 1 root root 1864 6月 23 16:54 mysql-community.repo
-rw-r–r– 1 root root 1885 2月 22 16:49 mysql-community-source.repo
[root@izuf6i3jkmikgmou78pwvfz yum.repos.d]#
3、原理总结
我们知道了：如何增强yum源固有的库？和如何自主选择安装库中的版本？从中，我们很容易明白：当你执行yum -y install的时候，其实就是去Yum源的地方去下载rpm包安装后的东东，所以如果我们需要yum源中本来不存在的或者未及时更新的包包，就要去官网下载rpm包，然后解压安装：
sudo yum localinstall platform-and-version-specific-package-name.rpm这个时候，yum源中就有了我们想要安装的版本；如果是最新的，默认就是启动的。如果你还想对安装的版本”为所欲为“，那么就需要enabled和disable部分包包：
yum-config-manager --disable mysql80-community
yum-config-manager --enable mysql80-community或者去修改配置文件：Besides using yum-config-manager or the dnf config-manager command, you can also select a release series by editing manually the/etc/yum.repos.d/mysql-community.repo file. This is a typical entry for a release series’ subrepository in the file:
，就是这样的流程。
好了，晚安。