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docker start起不來的解決辦法：1、檢查運(yùn)行狀態(tài)，然后通過“echo 3 > /proc/sys/vm/drop_caches”命令釋放被占用的內(nèi)存；2、通過“$netstat -nltp|grep …”命令檢查端口是否已經(jīng)被占用，如果上線后發(fā)現(xiàn)占有，則改為可用端口再重啟即可。
本教程操作環(huán)境：linux7.3系統(tǒng)、docker19.03版、Dell G3電腦。
docker start起不來怎么辦？
Docker無法正常啟動(dòng)的原因及解決辦法
概述
Docker啟動(dòng)異常表現(xiàn)
狀態(tài)反復(fù)restaring，用命令查看
$docker?ps?-a CONTAINER?ID????IMAGE??COMMAND???????CREATED??????STATUS???????PORTS????NAMES 21c09be88c11?????docker.xxxx.cn:5000/xxx-tes/xxx_tes:1.0.6???"/usr/local/tomcat..."???9?days?ago??????????Restarting?(1)?Less?than?a?second?ago??????????????????????xxx10
Docker日志有明顯問題：
$docker?logs?[容器名/容器ID] 比如： docker?logs?openresty
Docker啟動(dòng)異常的可能原因
內(nèi)存不夠
Docker 啟動(dòng)至少需要2G內(nèi)存，首先執(zhí)行free -mh命令查看剩余內(nèi)存是否足夠
直接查看內(nèi)存
$free?-mh ????????????total????????used????????free??????shared??buff/cache???available Mem:?????????15G?????????14G??????????627M????????195M????????636M?????726M Swap:?????????0B??????????0B??????????0B
分析日志
有時(shí)候一瞬間內(nèi)存過載溢出，導(dǎo)致部分進(jìn)程被殺死，看起來內(nèi)存也是夠用的，事實(shí)上docker還是會(huì)反復(fù)重啟，就需要通過docker日志和系統(tǒng)日志信的息來進(jìn)一步分析：
分析docker日志
查看docker日志看到內(nèi)存溢出的信息，要仔細(xì)翻閱才能找到信息，并不是在最下面
$docker?logs?[容器名/容器ID]|less? Java?HotSpot(TM)?64-Bit?Server?VM?warning:?INFO:?os::commit_memory(0x0000000769990000,?1449590784,?0)?failed;?error='Cannot?allocate?memory'?(errno=12) # #?There?is?insufficient?memory?for?the?Java?Runtime?Environment?to?continue. #?Native?memory?allocation?(malloc)?failed?to?allocate?1449590784?bytes?for?committing?reserved?memory. #?An?error?report?file?with?more?information?is?saved?as: #?//hs_err_pid1.log Java?HotSpot(TM)?64-Bit?Server?VM?warning:?INFO:?os::commit_memory(0x0000000769990000,?1449590784,?0)?failed;?error='Cannot?allocate?memory'?(errno=12) # #?There?is?insufficient?memory?for?the?Java?Runtime?Environment?to?continue. #?Native?memory?allocation?(malloc)?failed?to?allocate?1449590784?bytes?for?committing?reserved?memory. #?An?error?report?file?with?more?information?is?saved?as: #?/tmp/hs_err_pid1.log Java?HotSpot(TM)?64-Bit?Server?VM?warning:?INFO:?os::commit_memory(0x0000000769990000,?1449590784,?0)?failed;?error='Cannot?allocate?memory'?(errno=12) # #?There?is?insufficient?memory?for?the?Java?Runtime?Environment?to?continue. #?Native?memory?allocation?(malloc)?failed?to?allocate?1449590784?bytes?for?committing?reserved?memory. #?Can?not?save?log?file,?dump?to?screen.. # #?There?is?insufficient?memory?for?the?Java?Runtime?Environment?to?continue. #?Native?memory?allocation?(malloc)?failed?to?allocate?1449590784?bytes?for?committing?reserved?memory. #?Possible?reasons: #???The?system?is?out?of?physical?RAM?or?swap?space #???In?32?bit?mode,?the?process?size?limit?was?hit #?Possible?solutions: #???Reduce?memory?load?on?the?system #???Increase?physical?memory?or?swap?space #???Check?if?swap?backing?store?is?full #???Use?64?bit?Java?on?a?64?bit?OS #???Decrease?Java?heap?size?(-Xmx/-Xms) #???Decrease?number?of?Java?threads #???Decrease?Java?thread?stack?sizes?(-Xss) #???Set?larger?code?cache?with?-XX:ReservedCodeCacheSize= #?This?output?file?may?be?truncated?or?incomplete. # #??Out?of?Memory?Error?(os_linux.cpp:2756),?pid=1,?tid=140325689620224 # #?JRE?version:??(7.0_79-b15)?(build?) #?Java?VM:?Java?HotSpot(TM)?64-Bit?Server?VM?(24.79-b02?mixed?mode?linux-amd64?compressed?oops) #?Core?dump?written.?Default?location:?//core?or?core.1 #
分析系統(tǒng)日志
查看系統(tǒng)日志，發(fā)現(xiàn)有大量由于內(nèi)存溢出，進(jìn)程被殺死的記錄
$grep?-i?'Out?of?Memory'?/var/log/messages Apr??7?10:04:02?centos106?kernel:?Out?of?memory:?Kill?process?1192?(java)?score?54?or?sacrifice?child Apr??7?10:08:00?centos106?kernel:?Out?of?memory:?Kill?process?2301?(java)?score?54?or?sacrifice?child Apr??7?10:09:59?centos106?kernel:?Out?of?memory:?Kill?process?28145?(java)?score?52?or?sacrifice?child Apr??7?10:20:40?centos106?kernel:?Out?of?memory:?Kill?process?2976?(java)?score?54?or?sacrifice?child Apr??7?10:21:08?centos106?kernel:?Out?of?memory:?Kill?process?3577?(java)?score?47?or?sacrifice?child Apr??7?10:21:08?centos106?kernel:?Out?of?memory:?Kill?process?3631?(java)?score?47?or?sacrifice?child Apr??7?10:21:08?centos106?kernel:?Out?of?memory:?Kill?process?3634?(java)?score?47?or?sacrifice?child Apr??7?10:21:08?centos106?kernel:?Out?of?memory:?Kill?process?3640?(java)?score?47?or?sacrifice?child Apr??7?10:21:08?centos106?kernel:?Out?of?memory:?Kill?process?3654?(java)?score?47?or?sacrifice?child Apr??7?10:27:27?centos106?kernel:?Out?of?memory:?Kill?process?6998?(java)?score?51?or?sacrifice?child Apr??7?10:27:28?centos106?kernel:?Out?of?memory:?Kill?process?7027?(java)?score?52?or?sacrifice?child Apr??7?10:28:10?centos106?kernel:?Out?of?memory:?Kill?process?7571?(java)?score?42?or?sacrifice?child Apr??7?10:28:10?centos106?kernel:?Out?of?memory:?Kill?process?7586?(java)?score?42?or?sacrifice?child
端口沖突
該docker監(jiān)聽端口已經(jīng)被其他進(jìn)程占用，一般此種問題容易出現(xiàn)在新部署的服務(wù)，或在原有機(jī)器上部署新的后臺(tái)服務(wù)，所以在部署之前應(yīng)該執(zhí)行命令檢查端口是否已經(jīng)被占用，如果上線后發(fā)現(xiàn)占有則應(yīng)改為可用端口再重啟之。
檢查命令：????netstat?-nltp|grep?[規(guī)劃的端口號(hào)]
解決方案
內(nèi)存不夠的方案
進(jìn)程在運(yùn)行一段時(shí)間后占用大量?jī)?nèi)存，需要將其重啟。重啟命令可能有時(shí)并不起作用。主要檢查運(yùn)行狀態(tài)，如果未成功停止，則重新重啟；
elk日志收集程序或者其他java進(jìn)程占用過高，用top和ps命令排查，謹(jǐn)慎確定進(jìn)程的作用，在確保不影響業(yè)務(wù)的情況下，停止相關(guān)進(jìn)程；
釋放被占用的內(nèi)存（buff/cache）
?[root]#?sync??#將內(nèi)存數(shù)據(jù)寫入磁盤 ?[root]#?echo?3?>?/proc/sys/vm/drop_caches??#釋放被占用的內(nèi)存
有時(shí)候并不是buff/cache過高導(dǎo)致內(nèi)存不夠用，確實(shí)是被很多必要的進(jìn)程消耗掉了內(nèi)存，那就需要從機(jī)器資源分配使用的層面去考慮和解決了。
端口沖突的對(duì)策
一般此種問題容易出現(xiàn)在新部署的服務(wù)，或在原有機(jī)器上部署新的后臺(tái)服務(wù)，所以在部署之前應(yīng)該執(zhí)行命令檢查端口是否已經(jīng)被占用，如果上線后發(fā)現(xiàn)占有則應(yīng)改為可用端口再重啟之。
檢查命令：????$netstat?-nltp|grep?[規(guī)劃的端口號(hào)]
推薦學(xué)習(xí)：《docker視頻教程》
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