編譯安裝tomcat-native和tomcat-deamon以后,發現toomcat啟動很慢，好久才有響應。以下日志供參考：
11-Sep-2017 12:19:28.102 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/apache-tomcat-9.0/webapps/ROOT]
11-Sep-2017 12:19:28.667 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:20:34.870 WARNING [main] org.apache.catalina.util.SessionIdGeneratorBase.createSecureRandom Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [66,193] milliseconds.
11-Sep-2017 12:20:34.917 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/ROOT] has finished in [66,815] ms
11-Sep-2017 12:20:34.918 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/apache-tomcat-9.0/webapps/host-manager]
11-Sep-2017 12:20:35.004 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:20:35.013 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/host-manager] has finished in [96] ms
11-Sep-2017 12:20:35.014 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/apache-tomcat-9.0/webapps/manager]
11-Sep-2017 12:20:35.062 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:20:35.066 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/manager] has finished in [53] ms
11-Sep-2017 12:20:35.074 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
11-Sep-2017 12:20:35.105 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"]
11-Sep-2017 12:20:35.113 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 67067 ms
tomcat啟動耗時67067ms折合67秒,剛剛安裝的干凈tomcat,顯然不對勁。
有一條日志引起了我的注意:
11-Sep-2017 12:20:34.870 WARNING [main] org.apache.catalina.util.SessionIdGeneratorBase.createSecureRandom Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [66,193] milliseconds.
顯然tomcat執行到這里時出問題了,google了一下:"tomcat startup take long time SecureRandom",經過搜索,發現了一個解決方法
Slow startup on Tomcat 7.0.57 because of SecureRandom
問題緣由:當沒有足夠的entropy反饋給/dev/random時調用securerandom的時候可能引起阻塞。
解決方法1：
修改 /opt/jdk1.8/jre/jre/lib/security/java.security
securerandom.source=file:/dev/./urandom
解決方法2：安裝haveged
apt-get install haveged vim /etc/default/haveged #編輯配置文件,輸入下面一行 DAEMON_ARGS="-w 1024"
#刷新配置 update-rc.d haveged defaults
筆者采用了第二種方法,ubuntu16 amd64，64位系統,其他linux系統參考How to Setup Additional Entropy for Cloud Servers Using Haveged
同以上操作順利解決問題。
更新后重啟tomcat日志如下:
[/opt/apache-tomcat-9.0/webapps/ROOT]
11-Sep-2017 12:28:00.324 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:28:00.374 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/ROOT] has finished in [567] ms
11-Sep-2017 12:28:00.375 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/apache-tomcat-9.0/webapps/host-manager]
11-Sep-2017 12:28:00.448 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:28:00.456 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/host-manager] has finished in [80] ms
11-Sep-2017 12:28:00.456 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/apache-tomcat-9.0/webapps/manager]
11-Sep-2017 12:28:00.502 INFO [main] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
11-Sep-2017 12:28:00.504 INFO [main] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/opt/apache-tomcat-9.0/webapps/manager] has finished in [48] ms
11-Sep-2017 12:28:00.514 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
11-Sep-2017 12:28:00.545 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8009"]
11-Sep-2017 12:28:00.565 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 803 ms
參考：
Tomcat takes too much time to start - Java SecureRandom
How to Setup Additional Entropy for Cloud Servers Using Haveged