YUM：[Errno 14] problem making ssl connection
有时候在使用YUM的时候，你会出现如题所示的问题，具体如下：
[root@mha1 c++]# yum install -y glib2-devel libpcap-devel libnet-devel
Loaded plugins: fastestmirror, refresh-packagekit, security
Determining fastest mirrors
* extras: mirrors.163.com
* remi-safe: mirrors.thzhost.com
* updates: mirrors.aliyun.com
LocalPercona | 2.9 kB 00:00 ...
LocalPercona/primary_db | 16 kB 00:00 ...
http://download.fedoraproject.org/pub/epel/6/x86_64/repodata/repomd.xml: [Errno 14] problem making ssl connection
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: epel. Please verify its path and try again
[root@mha1 c++]# 对于该问题，需要首先禁用出问题的YUM源（enabled=0），然后安装ca-certificates包：
yum install ca-certificates
可以看到，上面出问题的是EPEL源。
先禁用：
[root@mha1 ~]# cat /etc/yum.repos.d/epel.repo
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=0
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch/debug
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/6/SRPMS
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
[root@mha1 ~]# 然后，安装软件包：
[root@mha1 ~]# yum install ca-certificates
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
* base: mirrors.btte.net
* extras: mirrors.163.com
* remi-safe: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.aliyun.com
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package ca-certificates.noarch 0:2010.63-3.el6_1.5 will be updated
---> Package ca-certificates.noarch 0:2015.2.6-65.0.1.el6_7 will be an update
--> Processing Dependency: p11-kit-trust >= 0.18.4-2 for package: ca-certificates-2015.2.6-65.0.1.el6_7.noarch
--> Processing Dependency: p11-kit >= 0.18.4-2 for package: ca-certificates-2015.2.6-65.0.1.el6_7.noarch
--> Running transaction check
---> Package p11-kit.x86_64 0:0.18.5-2.el6_5.2 will be installed
---> Package p11-kit-trust.x86_64 0:0.18.5-2.el6_5.2 will be installed
--> Processing Conflict: p11-kit-trust-0.18.5-2.el6_5.2.x86_64 conflicts nss < 3.14.3-33
--> Restarting Dependency Resolution with new changes.
--> Running transaction check
---> Package nss.x86_64 0:3.13.3-6.el6 will be updated
--> Processing Dependency: nss = 3.13.3-6.el6 for package: nss-tools-3.13.3-6.el6.x86_64
--> Processing Dependency: nss = 3.13.3-6.el6 for package: nss-sysinit-3.13.3-6.el6.x86_64
---> Package nss.x86_64 0:3.21.3-2.el6_8 will be an update
--> Processing Dependency: nss-util >= 3.21.0 for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: nss-softokn(x86-64) >= 3.14.3-22 for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: nspr >= 4.11.0 for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.21)(64bit) for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.17.1)(64bit) for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.15)(64bit) for package: nss-3.21.3-2.el6_8.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.14)(64bit) for package: nss-3.21.3-2.el6_8.x86_64
--> Running transaction check
---> Package nspr.x86_64 0:4.9-1.el6 will be updated
---> Package nspr.x86_64 0:4.11.0-1.el6 will be an update
---> Package nss-softokn.x86_64 0:3.12.9-11.el6 will be updated
---> Package nss-softokn.x86_64 0:3.14.3-23.3.el6_8 will be an update
--> Processing Dependency: nss-softokn-freebl(x86-64) >= 3.14.3-23.3.el6_8 for package: nss-softokn-3.14.3-23.3.el6_8.x86_64
---> Package nss-sysinit.x86_64 0:3.13.3-6.el6 will be updated
---> Package nss-sysinit.x86_64 0:3.21.3-2.el6_8 will be an update
---> Package nss-tools.x86_64 0:3.13.3-6.el6 will be updated
---> Package nss-tools.x86_64 0:3.21.3-2.el6_8 will be an update
---> Package nss-util.x86_64 0:3.13.3-2.el6 will be updated
---> Package nss-util.x86_64 0:3.21.3-1.el6_8 will be an update
--> Running transaction check
---> Package nss-softokn-freebl.x86_64 0:3.12.9-11.el6 will be updated
---> Package nss-softokn-freebl.x86_64 0:3.14.3-23.3.el6_8 will be an update
--> Finished Dependency Resolution
Dependencies Resolved
==================================================================================================================================================
Package Arch Version Repository Size
==================================================================================================================================================
Updating:
ca-certificates noarch 2015.2.6-65.0.1.el6_7 base 1.2 M
nss x86_64 3.21.3-2.el6_8 updates 859 k
Installing for dependencies:
p11-kit x86_64 0.18.5-2.el6_5.2 base 94 k
p11-kit-trust x86_64 0.18.5-2.el6_5.2 base 71 k
Updating for dependencies:
nspr x86_64 4.11.0-1.el6 base 114 k
nss-softokn x86_64 3.14.3-23.3.el6_8 updates 262 k
nss-softokn-freebl x86_64 3.14.3-23.3.el6_8 updates 168 k
nss-sysinit x86_64 3.21.3-2.el6_8 updates 47 k
nss-tools x86_64 3.21.3-2.el6_8 updates 437 k
nss-util x86_64 3.21.3-1.el6_8 updates 67 k
Transaction Summary
==================================================================================================================================================
Install 2 Package(s)
Upgrade 8 Package(s)
Total download size: 3.3 M
Is this ok [y/N]: y
Downloading Packages:
(1/10): ca-certificates-2015.2.6-65.0.1.el6_7.noarch.rpm | 1.2 MB 00:02
(2/10): nspr-4.11.0-1.el6.x86_64.rpm | 114 kB 00:00
(3/10): nss-3.21.3-2.el6_8.x86_64.rpm | 859 kB 00:01
(4/10): nss-softokn-3.14.3-23.3.el6_8.x86_64.rpm | 262 kB 00:00
(5/10): nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64.rpm | 168 kB 00:00
(6/10): nss-sysinit-3.21.3-2.el6_8.x86_64.rpm | 47 kB 00:00
(7/10): nss-tools-3.21.3-2.el6_8.x86_64.rpm | 437 kB 00:00
(8/10): nss-util-3.21.3-1.el6_8.x86_64.rpm | 67 kB 00:00
(9/10): p11-kit-0.18.5-2.el6_5.2.x86_64.rpm | 94 kB 00:00
(10/10): p11-kit-trust-0.18.5-2.el6_5.2.x86_64.rpm | 71 kB 00:00
--------------------------------------------------------------------------------------------------------------------------------------------------
Total 439 kB/s | 3.3 MB 00:07
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Updating : nspr-4.11.0-1.el6.x86_64 1/18
Updating : nss-util-3.21.3-1.el6_8.x86_64 2/18
Updating : nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64 3/18
Installing : p11-kit-0.18.5-2.el6_5.2.x86_64 4/18
Updating : nss-softokn-3.14.3-23.3.el6_8.x86_64 5/18
Updating : nss-sysinit-3.21.3-2.el6_8.x86_64 6/18
Updating : nss-3.21.3-2.el6_8.x86_64 7/18
Installing : p11-kit-trust-0.18.5-2.el6_5.2.x86_64 8/18
Updating : ca-certificates-2015.2.6-65.0.1.el6_7.noarch 9/18
Updating : nss-tools-3.21.3-2.el6_8.x86_64 10/18
Cleanup : nss-tools-3.13.3-6.el6.x86_64 11/18
Cleanup : ca-certificates-2010.63-3.el6_1.5.noarch 12/18
Cleanup : nss-sysinit-3.13.3-6.el6.x86_64 13/18
Cleanup : nss-3.13.3-6.el6.x86_64 14/18
Cleanup : nss-softokn-3.12.9-11.el6.x86_64 15/18
Cleanup : nss-util-3.13.3-2.el6.x86_64 16/18
Cleanup : nspr-4.9-1.el6.x86_64 17/18
Cleanup : nss-softokn-freebl-3.12.9-11.el6.x86_64 18/18
Verifying : p11-kit-0.18.5-2.el6_5.2.x86_64 1/18
Verifying : nss-softokn-3.14.3-23.3.el6_8.x86_64 2/18
Verifying : nspr-4.11.0-1.el6.x86_64 3/18
Verifying : nss-3.21.3-2.el6_8.x86_64 4/18
Verifying : nss-tools-3.21.3-2.el6_8.x86_64 5/18
Verifying : nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64 6/18
Verifying : nss-sysinit-3.21.3-2.el6_8.x86_64 7/18
Verifying : ca-certificates-2015.2.6-65.0.1.el6_7.noarch 8/18
Verifying : p11-kit-trust-0.18.5-2.el6_5.2.x86_64 9/18
Verifying : nss-util-3.21.3-1.el6_8.x86_64 10/18
Verifying : nspr-4.9-1.el6.x86_64 11/18
Verifying : nss-3.13.3-6.el6.x86_64 12/18
Verifying : nss-sysinit-3.13.3-6.el6.x86_64 13/18
Verifying : nss-tools-3.13.3-6.el6.x86_64 14/18
Verifying : ca-certificates-2010.63-3.el6_1.5.noarch 15/18
Verifying : nss-util-3.13.3-2.el6.x86_64 16/18
Verifying : nss-softokn-3.12.9-11.el6.x86_64 17/18
Verifying : nss-softokn-freebl-3.12.9-11.el6.x86_64 18/18
Dependency Installed:
p11-kit.x86_64 0:0.18.5-2.el6_5.2 p11-kit-trust.x86_64 0:0.18.5-2.el6_5.2
Updated:
ca-certificates.noarch 0:2015.2.6-65.0.1.el6_7 nss.x86_64 0:3.21.3-2.el6_8
Dependency Updated:
nspr.x86_64 0:4.11.0-1.el6 nss-softokn.x86_64 0:3.14.3-23.3.el6_8 nss-softokn-freebl.x86_64 0:3.14.3-23.3.el6_8
nss-sysinit.x86_64 0:3.21.3-2.el6_8 nss-tools.x86_64 0:3.21.3-2.el6_8 nss-util.x86_64 0:3.21.3-1.el6_8
Complete!
[root@mha1 ~]# 然后，重新启用YUM源：
[root@mha1 ~]# cat /etc/yum.repos.d/epel.repo
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch/debug
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/6/SRPMS
#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
[root@mha1 ~]# 再次尝试之前失败的安装：
[root@mha1 ~]# yum install -y glib2-devel libpcap-devel libnet-devel
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
* base: mirrors.btte.net
* extras: mirrors.163.com
* remi-safe: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.aliyun.com
epel | 4.3 kB 00:00
epel/primary_db | 5.9 MB 00:17
Setting up Install Process
Package glib2-devel-2.28.8-5.el6.x86_64 already installed and latest version
Package 14:libpcap-devel-1.4.0-4.20130826git2dbcaa1.el6.x86_64 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package libnet-devel.x86_64 0:1.1.6-7.el6 will be installed
--> Processing Dependency: libnet(x86-64) = 1.1.6-7.el6 for package: libnet-devel-1.1.6-7.el6.x86_64
--> Processing Dependency: libnet.so.1()(64bit) for package: libnet-devel-1.1.6-7.el6.x86_64
--> Running transaction check
---> Package libnet.x86_64 0:1.1.6-7.el6 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
==================================================================================================================================================
Package Arch Version Repository Size
==================================================================================================================================================
Installing:
libnet-devel x86_64 1.1.6-7.el6 epel 181 k
Installing for dependencies:
libnet x86_64 1.1.6-7.el6 epel 58 k
Transaction Summary
==================================================================================================================================================
Install 2 Package(s)
Total download size: 239 k
Installed size: 1.4 M
Downloading Packages:
(1/2): libnet-1.1.6-7.el6.x86_64.rpm | 58 kB 00:00
(2/2): libnet-devel-1.1.6-7.el6.x86_64.rpm | 181 kB 00:00
--------------------------------------------------------------------------------------------------------------------------------------------------
Total 110 kB/s | 239 kB 00:02
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : libnet-1.1.6-7.el6.x86_64 1/2
Installing : libnet-devel-1.1.6-7.el6.x86_64 2/2
Verifying : libnet-1.1.6-7.el6.x86_64 1/2
Verifying : libnet-devel-1.1.6-7.el6.x86_64 2/2
Installed:
libnet-devel.x86_64 0:1.1.6-7.el6
Dependency Installed:
libnet.x86_64 0:1.1.6-7.el6
Complete!
[root@mha1 ~]# 可以看到，已经没问题了。
————————————
Done。