Devstack — screen 調試工具的使用

目錄

• 目錄
• 爲何要使用 screen 工具
  • 啓動 screen
  • screen 的切換經常使用
  • 退出和從新鏈接 screen
  • Restart Openstack Services
• screen 指令選項總覽
  • Openstack 重啓指令
    • glance-api
    • glance-registry
    • nova-api
    • nova-conduter
    • nova-crt
    • nova-network
    • nova-scheduter
    • nova-novnc
    • nova-cauth
    • nova-cpu
    • c-api
    • c-sch
    • c-vol

爲何要使用 screen 工具 ？

當 Devstack 編譯安裝完 OpenStack 後，咱們是不能經過 init 腳本或者 service 指令來與各個 Openstack Services 進行交互的。
也就是說咱們沒法像使用 RDO 安裝那樣能夠經過 systemctl restart openstack-nova-api.serice 來重啓 nova-api 服務。
由於 Devstack 的設計初衷是便於 Openstack developers 開發和調試 Openstack 代碼，因此 Devstack 只能經過 screen 來啓動服務，並且每個 Openstack Services 都是一個子 screen 。Devstack 部署的 Openstack 相信你們都會碰見一個問題，當物理機重啓後 Services 怎麼重啓，其實只須要執行 ./rejoin-stack.sh就行了，其原理跟啓動 screen 是同樣的，將沒有啓動的 Services 啓動，已經啓動的不會被覆蓋，啓動完成後自動進入 screen 。在 screen 中咱們不單單能夠啓動 Services ，咱們還可以很是清晰簡便的切換查看各個 Services 的 Log 。本篇主要介紹了 screen 的使用，應該是多有 Openstack 開發者的必備技能吧。

啓動 screen

screen -x stack

注意：若是啓動失敗，能夠嘗試在執行下面的指令以後在從新嘗試啓動：

script /dev/null

能夠看見 Terminal 最下方有一串白色的字符串，其中的每個數字對應一個子 screen 也就是一個 Openstack services 。
咱們能夠經過快捷鍵+數字的組合來切換到對應的子 screen 。’ * ‘ 所在的處的位置表示當前的 screen 是該 Service 的 screen。EXAMPLE:

14$(L) c-api  15-$(L) c-sch   16$(L) c-vol*

screen 的切換(經常使用)

• CTRL+a + number ：切換到數字 number 對應的子 screen 中(number == 0 ⇒ shell)
  

• CTRL + a + ’ ⇒ 輸入number：當 number > 10 時，可使用這種方法來切換，固然 number < 10 時，也可使用。 推薦*

• CTRL + a + n ：切換到下一個 screen

• CTRL + a + p：切換到前一個 screen

• CTRL + a + a：返回上一個 screen

• CRTL + a + 稍等一秒 + shift + ‘：顯示全部的 screen 的列表

• CTRL + [：開始滾動模式 ，而後可使用上下左右鍵滾屏

• CTRL + ]：退出滾動模式

• CTRL + a + H ：保存 screen 到日誌文件，再按一次中止保存

• CTRL + a + ?：獲取幫助信息

退出和從新鏈接 screen

• 退出：

  1. CRTL + a + ’ ⇒ 輸入 0 ，而後再輸入screen -d
  2. CRTL + a + d

• 從新鏈接：

#查看當前用戶啓動的 screen
fanguiju@jmilkfan:~$ screen -ls   
There is a screen on:
    20569.stack (08/02/16 11:36:47) (Detached)
1 Socket in /var/run/screen/S-fanguiju.

#上一條指令的Output
fanguiju@jmilkfan:~$ screen -r 20569

Restart Openstack Services

• CTRL + c：終止一個 screen ，Stop the services

• 進入但願 Restart 的 Openstack Services 的 screen 中，而後輸入 CTRL + c 結束這個進程，輸入 ↑並從新執行上一條指令。
  

screen 指令選項總覽

fanguiju@fanguiju:~/devstack$ screen --help 
Use: screen [-opts] [cmd [args]]
 or: screen -r [host.tty]

Options:
-4 Resolve hostnames only to IPv4 addresses. -6 Resolve hostnames only to IPv6 addresses. -a Force all capabilities into each window's termcap. -A -[r|R] Adapt all windows to the new display width & height. -c file Read configuration file instead of '.screenrc'. -d (-r) Detach the elsewhere running screen (and reattach here). -dmS name Start as daemon: Screen session in detached mode. -D (-r) Detach and logout remote (and reattach here). -D -RR Do whatever is needed to get a screen session. -e xy Change command characters. -f Flow control on, -fn = off, -fa = auto. -h lines Set the size of the scrollback history buffer. -i Interrupt output sooner when flow control is on. -l Login mode on (update /var/run/utmp), -ln = off. -ls [match] or -list. Do nothing, just list our SockDir [on possible matches]. -L Turn on output logging. -m ignore $STY variable, do create a new screen session. -O Choose optimal output rather than exact vt100 emulation. -p window Preselect the named window if it exists. -q Quiet startup. Exits with non-zero return code if unsuccessful. -r [session] Reattach to a detached screen process. -R Reattach if possible, otherwise start a new session. -s shell Shell to execute rather than $SHELL. -S sockname Name this session <pid>.sockname instead of <pid>.<tty>.<host>. -t title Set title. (window's name). -T term Use term as $TERM for windows, rather than "screen". -U Tell screen to use UTF-8 encoding. -v Print "Screen version 4.01.00devel (GNU) 2-May-06". -wipe [match] Do nothing, just clean up SockDir [on possible matches]. -x Attach to a not detached screen. (Multi display mode). -X Execute <cmd> as a screen command in the specified session. 

Openstack 重啓指令

screen 有一個很是不方便的地方就是，有些電腦不能經過 CTRL + [|] 來實現屏幕的滾動，這根本沒法很好的觀察 Log ，因此建議將啓動指令 Copy 另一個 Terminal 執行。
注意：下列的指令的/opt/stack/參數因各人的安裝路徑不一樣而異。
restart glance:

glance-api

/usr/local/bin/glance-api --config-file=/etc/glance/glance-api.conf & echo $! >/opt/stack/status/stack/g-api.pid; fg || echo "g-api failed to start" | tee "/opt/stack/status/stack/g-api.failure"

glance-registry

/usr/local/bin/glance-registry --config-file=/etc/glance/glance-registry.conf & echo $! >/opt/stack/status/stack/g-reg.pid; fg || echo "g-reg failed to start" | tee "/opt/stack/status/stack/g-reg.failure"

nova-api

sudo /usr/local/bin/nova-api & echo $! >/opt/stack/status/stack/n-api.pid; fg || echo "n-api failed to start" | tee "/opt/stack/status/stack/n-api.failure"

nova-conduter

/usr/local/bin/nova-conductor --config-file /etc/nova/nova.conf & echo $! >/opt/stack/status/stack/n-cond.pid; fg || echo "n-cond failed to start" | tee "/opt/stack/status/stack/n-cond.failure"

nova-crt

/usr/local/bin/nova-cert --config-file /etc/nova/nova.conf & echo $! >/opt/stack/status/stack/n-crt.pid; fg || echo "n-crt failed to start" | tee "/opt/stack/status/stack/n-crt.failure"

nova-network

/usr/local/bin/nova-network --config-file /etc/nova/nova.conf & echo $! >/opt/stack/status/stack/n-net.pid; fg || echo "n-net failed to start" | tee "/opt/stack/status/stack/n-net.failure"

nova-scheduter

/usr/local/bin/nova-scheduler --config-file /etc/nova/nova.conf & echo $! >/opt/stack/status/stack/n-sch.pid; fg || echo "n-sch failed to start" | tee "/opt/stack/status/stack/n-sch.failure"

nova-novnc

/usr/local/bin/nova-novncproxy --config-file /etc/nova/nova.conf --web /opt/stack/noVNC & echo $! >/opt/stack/status/stack/n-novnc.pid; fg || echo "n-novnc failed to start" | tee "/opt/stack/status/stack/n-novnc.failure"

nova-cauth

/usr/local/bin/nova-consoleauth --config-file /etc/nova/nova.conf & echo $! >/opt/stack/status/stack/n-cauth.pid; fg || echo "n-cauth failed to start" | tee "/opt/stack/status/stack/n-cauth.failure"

nova-cpu

sg libvirtd '/usr/local/bin/nova-compute --config-file /etc/nova/nova.conf' & echo $! >/opt/stack/status/stack/n-cpu.pid; fg || echo "n-cpu failed to start" | tee "/opt/stack/status/stack/n-cpu.failure"

restart cinder:

c-api

/usr/local/bin/cinder-api --config-file /etc/cinder/cinder.conf & echo $! >/opt/stack/status/stack/c-api.pid; fg || echo "c-api failed to start" | tee "/opt/stack/status/stack/c-api.failure"

c-sch

/usr/local/bin/cinder-scheduler --config-file /etc/cinder/cinder.conf & echo $! >/opt/stack/status/stack/c-sch.pid; fg || echo "c-sch failed to start" | tee "/opt/stack/status/stack/c-sch.failure"

c-vol

/usr/local/bin/cinder-volume --config-file /etc/cinder/cinder.conf & echo $! >/opt/stack/status/stack/c-vol.pid; fg || echo "c-vol failed to start" | tee "/opt/stack/status/stack/c-vol.failure"