Docker Tomcat7容器并不总是正确启动

Question

我正在用Docker做一些测试，我在启动tomcat7容器时遇到了问题，它有时正确启动，有时不正确。下面是几次尝试的示例

fred@fred-Latitude-E6520:~/docker/test2$ docker.io run  tomcat7
 * Starting Tomcat servlet engine tomcat7
   ...done.
May 04, 2014 5:31:19 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
May 04, 2014 5:31:19 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.52 (Ubuntu)
May 04, 2014 5:31:19 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory /var/lib/tomcat7/webapps/ROOT
May 04, 2014 5:31:20 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8080"]
May 04, 2014 5:31:20 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 886 ms
fred@fred-Latitude-E6520:~/docker/test2$ docker.io run  tomcat7
 * Starting Tomcat servlet engine tomcat7
   ...fail!
fred@fred-Latitude-E6520:~/docker/test2$ docker.io run  tomcat7
 * Starting Tomcat servlet engine tomcat7
   ...fail!
fred@fred-Latitude-E6520:~/docker/test2$ docker.io run  tomcat7
 * Starting Tomcat servlet engine tomcat7
   ...done.
May 04, 2014 5:32:04 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
May 04, 2014 5:32:04 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.52 (Ubuntu)
May 04, 2014 5:32:04 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory /var/lib/tomcat7/webapps/ROOT
May 04, 2014 5:32:05 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8080"]
May 04, 2014 5:32:05 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 833 ms

我的Dockerfile：

FROM ubuntu:14.04
# Update Ubuntu
RUN apt-get update && apt-get -y upgrade
# Add oracle java 7 repository
RUN apt-get -y install software-properties-common
RUN add-apt-repository ppa:webupd8team/java
RUN apt-get -y update
# Accept the Oracle Java license
RUN echo "oracle-java7-installer shared/accepted-oracle-license-v1-1 boolean true" | debconf-set-selections
# Install Oracle Java
RUN apt-get -y install oracle-java7-installer
# Install tomcat
RUN apt-get -y install tomcat7
RUN echo "JAVA_HOME=/usr/lib/jvm/java-7-oracle" >> /etc/default/tomcat7
EXPOSE 8080
# Start Tomcat, after starting Tomcat the container will stop. So use a 'trick' to keep it running.
CMD service tomcat7 start && tail -f /var/log/tomcat7/catalina.out

当它失败时，我怎么能看到哪里出了问题呢？

Docker启动是否有超时？如果我的容器没有在x秒内启动，Docker会认为它失败了吗？

Answer 1

如果失败，请执行以下操作：

docker logs $(docker -q -a -l)

这将告诉你为什么它失败了。

我认为问题可能是tomcat没有在前台运行，所以您的docker容器结束了，您可能想尝试在supervisor下运行tomcat，并将：

CMD ["supervisord", "-n"]

作为你的命令。

这将告诉supervisor在前台运行，它将为您运行tomcat。你可以通过一个快速的google找到很多tomcat supervisor的例子。这应该很容易做到。

编辑：

或者，使用以下命令在前台运行tomcat

tomcat/bin/catalina.sh run

这应该有相同的影响，所以你的cmd应该是这样的：

CMD ["<path/to/tomcat>/bin/catalina.sh", "run"]

希望这能有所帮助