发现一个奇怪的现象，gitlab有时打开报502，多刷几次可以正常打开。所以并不是端口被占用
网上提供了一个分析的方法：
1、gitlab-ctl status
查看进程是否正常启动
2、/var/log/gitlab
下的日志有没有报错
3、gitlab-ctl tail [process name]
查看对应进程的情况

参考资料：
https://www.liangzl.com/get-article-detail-27713.html
https://segmentfault.com/a/1190000017436142

yum update时报错：
错误：rpmdb: BDB0113 Thread/process 9751/139849321973824 failed: BDB1507 Thread died in Berkeley DB library
错误：db5 错误(-30973) 来自 dbenv->failchk：BDB0087 DB_RUNRECOVERY: Fatal error, run database recovery
错误：无法使用 db5 - (-30973) 打开 Packages 索引
错误：无法从 /var/lib/rpm 打开软件包数据库
CRITICAL:yum.main:
Error: rpmdb open failed

解决办法：
cd /var/lib/rpm
rm -rf __db*
rpm --rebuilddb
yum repolist

再执行：
yum update

1、由于网络不好，导致yum命令中断，再次执行时提示
Another app is currently holding the yum lock; waiting for it to exit…

2、解决办法
rm -f /var/run/yum.pid
yum install yum-utils
yum clean all
yum-complete-transaction --cleanup-only
yum history redo last

3、安装yum-utils包时提示
There are unfinished transactions remaining. You might consider running yum-complete-transaction, or "yum-complete-transaction --cleanup-only" and "yum history redo last", first to finish them. If those don't work you'll have to try removing/installing packages by hand (maybe package-cleanup can help).
The program yum-complete-transaction is found in the yum-utils package.
以后yum-utils包要事先安装好

4、RPM数据库错误问题
事务处理完后，执行yum update还是报错：
--> 解决依赖关系完成
错误：软件包：7:device-mapper-libs-1.02.164-7.el7_8.1.x86_64 (@updates)
需要：device-mapper = 7:1.02.164-7.el7_8.1
正在删除: 7:device-mapper-1.02.164-7.el7_8.1.x86_64 (@updates)
device-mapper = 7:1.02.164-7.el7_8.1
更新，由: 7:device-mapper-1.02.164-7.el7_8.2.x86_64 (updates)
device-mapper = 7:1.02.164-7.el7_8.2
可用: 7:device-mapper-1.02.164-7.el7.x86_64 (base)
device-mapper = 7:1.02.164-7.el7
您可以尝试添加 --skip-broken 选项来解决该问题
** 发现 6 个已存在的 RPM 数据库问题， 'yum check' 输出如下：
7:device-mapper-libs-1.02.164-7.el7_8.2.x86_64 是 7:device-mapper-libs-1.02.164-7.el7_8.1.x86_64 的副本
7:device-mapper-libs-1.02.164-7.el7_8.2.x86_64 有缺少的需求 device-mapper = ('7', '1.02.164', '7.el7_8.2')
mesa-khr-devel-18.3.4-7.el7_8.1.x86_64 是 mesa-khr-devel-18.3.4-7.el7.x86_64 的副本
mesa-libglapi-18.3.4-7.el7_8.1.x86_64 是 mesa-libglapi-18.3.4-7.el7.x86_64 的副本
systemd-219-73.el7_8.6.x86_64 是 systemd-219-73.el7_8.5.x86_64 的副本
systemd-libs-219-73.el7_8.6.x86_64 是 systemd-libs-219-73.el7_8.5.x86_64 的副本
Warning: Some duplicates were not removed because they are required by installed packages.
You can try --cleandupes with --removenewestdupes, or review them with --dupes and remove manually.

现象是本机rpm数据库里记录了某个rpm包多个版本（可能事实上只装了一个版本）

查看软件包信息，发现存在多条信息：
rpm -qa | grep systemd
systemd-libs-219-73.el7_8.6.x86_64
systemd-219-73.el7_8.6.x86_64
systemd-libs-219-73.el7_8.5.x86_64
systemd-219-73.el7_8.5.x86_64
systemd-sysv-219-73.el7_8.5.x86_64

多了两条重复的：
systemd-libs-219-73.el7_8.5.x86_64
systemd-219-73.el7_8.5.x86_64

先解决xxx是xxx的副本：
rpm -e --noscripts device-mapper-libs-1.02.164-7.el7_8.2.x86_64
rpm -e --noscripts mesa-khr-devel-18.3.4-7.el7_8.1.x86_64
rpm -e --noscripts mesa-libglapi-18.3.4-7.el7_8.1.x86_64
rpm -e --noscripts systemd-219-73.el7_8.6.x86_64
rpm -e --noscripts systemd-libs-219-73.el7_8.6.x86_64

清理冲突：
package-cleanup --cleandupes

重新执行yum update，解决

现象是docker stop执行成功，但是docker ps中容器还是up状态

1、试试kill命令
docker kill nginx

2、重启docker服务
systemctl restart docker

3、再启动服务
docker start nginx

原因为nginx对目录没有写文件权限，代码是存在宿主机的，文件夹权限为root用户

1、登陆nginx容器环境
docker exec -it nginx /bin/bash

2、查看目录/var/www/html都是root用户权限
ls -al /var/www/html

3、查看容器用户
cat /etc/passwd
发现：
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
而nginx一般是用www-data用户来运行，它的家目录就是/var/www

4、将/var/www下改为www-data用户
cd /var/www
chown -R www-data:www-data ./

5、再次尝试，可以更新了

6、查看宿主机目录权限有没有变
ls -al /appserver/code/
drwxr-xr-x 8 33 33 4096 4月 12 08:19 wordpress
也变成了uid为33，因为是目录映射到容器中。容器中的改动也反映在宿主机上

1、安装软件包
yum groupinstall "fonts"

2、修改/etc/locale.conf
LANG=zh_CN.utf8

3、重启
reboot

1、gitlab是什么
gitlab是git仓库的管理工具，提供web页面方便用户使用。
gitlab-ce和gitlab-ee，ce是社区版，ee是企业版，企业版有些功能需要付费使用。

2、从官方仓库上安装gitlab
添加官方仓库：
curl -L https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.rpm.sh | sudo bash

3、安装postfix
sudo yum install postfix
sudo systemctl enable postfix
sudo systemctl start postfix

4、安装gitlab
yum install gitlab-ce

5、安装完成后会有提示信息
Thank you for installing GitLab!
GitLab was unable to detect a valid hostname for your instance.
Please configure a URL for your GitLab instance by setting `external_url`
configuration in /etc/gitlab/gitlab.rb file.
Then, you can start your GitLab instance by running the following command:
sudo gitlab-ctl reconfigure

For a comprehensive list of configuration options please see the Omnibus GitLab readme
https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/README.md

GitLab now ships with a newer version of PostgreSQL (11.7), but it is not yet
enabled by default. To upgrade, please see:
https://docs.gitlab.com/omnibus/settings/database.html#upgrade-packaged-postgresql-server

6、编辑/etc/gitlab/gitlab.rb
将：
# nginx['listen_port'] = nil
修改为：
nginx['listen_port'] = 8888
将：
external_url 'http://gitlab.example.com'
修改为：
external_url 'http://你的IP地址:8888'
注：这里external_url需要加上端口，否则使用http克隆和查看文件，链接里会没有端口

继续阅读centos安装gitlab-ce →