Kubernetes Scheduler是一个策略丰富、拓扑感知、工作负载特定的功能，调度器显著影响可用性、性能和容量。调度器需要考虑个人和集体的资源要求、服务质量要求、硬件/软件/政策约束、亲和力和反亲和力规范、数据局部性、负载间干扰、完成期限等。工作负载特定的要求必要时将通过 API 暴露。
kube-scheduler是Kube-Master相关的3个服务之一(ApiServer、Controller Manager、Scheduler)，是有状态的服务，会修改集群的状态信息。
如果多个master节点上的相关服务同时生效，则会有同步与一致性问题，所以多master节点中的kube-scheduler服务只能是主备的关系，kukubernetes采用租赁锁（lease-lock）实现leader的选举，具体到kube-scheduler，设置启动参数"--leader-elect=true"。
集群规划
| 主机名 | 角色 | IP地址 |
|---|---|---|
| mfyxw30.mfyxw.com | kube-scheduler | 192.168.80.30 |
| mfyxw40.mfyxw.com | kube-scheduler | 192.168.80.40 |
1.创建kube-scheduler启动脚本
在mfyxw30.mfyxw.com主机上创建kube-scheduler启动脚本
[root@mfyxw30 ~]# cat > /opt/kubernetes/server/bin/kube-scheduler.sh << EOF
#!/bin/sh
./kube-scheduler \\
--leader-elect \\
--log-dir /data/logs/kubernetes/kube-scheduler \\
--master http://127.0.0.1:8080 \\
--v 2
EOF
在mfyxw40.mfyxw.com主机上创建kube-scheduler启动脚本
[root@mfyxw40 ~]# cat > /opt/kubernetes/server/bin/kube-scheduler.sh << EOF
#!/bin/sh
./kube-scheduler \\
--leader-elect \\
--log-dir /data/logs/kubernetes/kube-scheduler \\
--master http://127.0.0.1:8080 \\
--v 2
EOF
2.调整文件权限，创建目录
在mfyxw30.mfyxw.com主机上调整kube-scheduler.sh文件权限，创建目录/data/logs/kubernetes/kube-scheduler
[root@mfyxw30 ~]# chmod +x /opt/kubernetes/server/bin/kube-scheduler.sh
[root@mfyxw30 ~]# mkdir -p /data/logs/kubernetes/kube-scheduler
在mfyxw40.mfyxw.com主机上调整kube-scheduler.sh文件权限，创建目录/data/logs/kubernetes/kube-scheduler
[root@mfyxw40 ~]# chmod +x /opt/kubernetes/server/bin/kube-scheduler.sh
[root@mfyxw40 ~]# mkdir -p /data/logs/kubernetes/kube-scheduler
3.为kube-scheduler创建supervisor配置文件
在mfyxw30.mfyxw.com主机上，为kube-scheduler创建supervisor配置文件
[root@mfyxw30 ~]# cat > /etc/supervisord.d/kube-scheduler.ini << EOF
[program:kube-scheduler-80-30]
command=/opt/kubernetes/server/bin/kube-scheduler.sh ; the program (relative uses PATH, can take args)
numprocs=1 ; number of processes copies to start (def 1)
directory=/opt/kubernetes/server/bin ; directory to cwd to before exec (def no cwd)
autostart=true ; start at supervisord start (default: true)
autorestart=true ; retstart at unexpected quit (default: true)
startsecs=22 ; number of secs prog must stay running (def. 1)
startretries=3 ; max # of serial start failures (default 3)
exitcodes=0,2 ; 'expected' exit codes for process (default 0,2)
stopsignal=QUIT ; signal used to kill process (default TERM)
stopwaitsecs=10 ; max num secs to wait b4 SIGKILL (default 10)
user=root ; setuid to this UNIX account to run the program
redirect_stderr=false ; redirect proc stderr to stdout (default false)
stdout_logfile=/data/logs/kubernetes/kube-scheduler/scheduler.stdout.log ; stdout log path, NONE for none; default AUTO
stdout_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stdout_logfile_backups=4 ; # of stdout logfile backups (default 10)
stdout_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stdout_events_enabled=false ; emit events on stdout writes (default false)
stderr_logfile=/data/logs/kubernetes/kube-scheduler/scheduler.stderr.log ; stderr log path, NONE for none; default AUTO
stderr_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stderr_logfile_backups=4 ; # of stderr logfile backups (default 10)
stderr_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stderr_events_enabled=false ; emit events on stderr writes (default false)
EOF
在mfyxw40.mfyxw.com主机上，为kube-scheduler创建supervisor配置文件
[root@mfyxw40 ~]# cat > /etc/supervisord.d/kube-scheduler.ini << EOF
[program:kube-scheduler-80-40]
command=/opt/kubernetes/server/bin/kube-scheduler.sh ; the program (relative uses PATH, can take args)
numprocs=1 ; number of processes copies to start (def 1)
directory=/opt/kubernetes/server/bin ; directory to cwd to before exec (def no cwd)
autostart=true ; start at supervisord start (default: true)
autorestart=true ; retstart at unexpected quit (default: true)
startsecs=22 ; number of secs prog must stay running (def. 1)
startretries=3 ; max # of serial start failures (default 3)
exitcodes=0,2 ; 'expected' exit codes for process (default 0,2)
stopsignal=QUIT ; signal used to kill process (default TERM)
stopwaitsecs=10 ; max num secs to wait b4 SIGKILL (default 10)
user=root ; setuid to this UNIX account to run the program
redirect_stderr=false ; redirect proc stderr to stdout (default false)
stdout_logfile=/data/logs/kubernetes/kube-scheduler/scheduler.stdout.log ; stdout log path, NONE for none; default AUTO
stdout_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stdout_logfile_backups=4 ; # of stdout logfile backups (default 10)
stdout_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stdout_events_enabled=false ; emit events on stdout writes (default false)
stderr_logfile=/data/logs/kubernetes/kube-scheduler/scheduler.stderr.log ; stderr log path, NONE for none; default AUTO
stderr_logfile_maxbytes=64MB ; max # logfile bytes b4 rotation (default 50MB)
stderr_logfile_backups=4 ; # of stderr logfile backups (default 10)
stderr_capture_maxbytes=1MB ; number of bytes in 'capturemode' (default 0)
stderr_events_enabled=false ; emit events on stderr writes (default false)
EOF
4.启动服务并检查
在mfyxw30.mfyxw.com主机上启动kube-scheduler服务并检查
[root@mfyxw30 ~]# supervisorctl update
[root@mfyxw30 ~]# supervisorctl status
在mfyxw40.mfyxw.com主机上启动kube-scheduler服务并检查
[root@mfyxw40 ~]# supervisorctl update
[root@mfyxw40 ~]# supervisorctl status
5.为kubectl创建链接并查看集群健康
在mfyxw30.mfyxw.com主机上为kubectl创建链接并查看集群健康
[root@mfyxw30 ~]# ln -s /opt/kubernetes/server/bin/kubectl /usr/bin/kubectl
[root@mfyxw30 ~]# kubectl get cs
在mfyxw40.mfyxw.com主机上为kubectl创建链接并查看集群健康
[root@mfyxw40 ~]# ln -s /opt/kubernetes/server/bin/kubectl /usr/bin/kubectl
[root@mfyxw40 ~]# kubectl get cs
