Reto Höhener's questions

• What is your experience? Can you confirm my experimental findings?
• Can I generally use total RAM - 600 MB, or 0.4 * total RAM?
• Or is it always trial and error, and hoping that it is low enough?

Context: I'm trying to set up jenkins on a T3 instance, experimenting with Ubuntu Server 16.04 and 18.04.

I started with a t3.micro instance (1 GB RAM), but found the OOM killer killing my java process, as soon as I use more than about -Xmx400m, which seems kind of low. I was expecting to be able to use more like -Xmx750m.

Does this mean Ubuntu Server requires about 600 MB to work?

The problem is that the java process starts, even if I set both -Xms and -Xmx to a very high value, like 700m. The process is killed only later when I make the first request to the website.

I now experiment with a t3.small instance (2 GB of RAM), but am again very unsure about what to configure.

On Windows it is kind of deterministic: I set both -Xms and -Xmx to the same value. If the service fails to start, the value was too high. If the service starts successfully, the value is fine, and the memory is reserved for my process.

Some background:

• https://plumbr.io/blog/memory-leaks/why-does-my-java-process-consume-more-memory-than-xmx
• https://support.cloudbees.com/hc/en-us/articles/115002718531-Memory-Problem-Process-killed-by-OOM-Killer
• Avoid linux out-of-memory application teardown
• Effects of configuring vm.overcommit_memory
• PostgreSQL seems to have a similar problem: https://dba.stackexchange.com/questions/170596/permanently-disable-oom-killer-for-postgres (and https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-MEMORY-OVERCOMMIT)

I bought some Office 365 license and learned that I automatically got a free basic Azure AD along with that.

So now I joined my first PC to the Azure AD and logged in with an Office 365 user:

[email protected]

but, the %userprofile% turned out to be:

C:\Users\FirstLast (C:\Users\RetoHöhener)

I expected:

C:\Users\first.last (C:\Users\reto.hoehener)

After some googling I found that this is the sAMAccountName (correct?).

I cannot figure out how to change the SAM account name in the Azure AD web admin application. I am missing a page that corresponds to this classical AD dialog:

FirstLast seems like a very inconvenient default because e.g. my last name contains a german umlaut so my userprofile would also contain a special character, which will probably break countless applications.

See also:

• https://stackoverflow.com/questions/33016155/azure-ad-and-windows-10-and-username
• https://community.spiceworks.com/topic/2034721-set-azure-ad-join-default-user-profile-name

Is this expected behaviour? Will the global web.xml not be picked up in the deployment scenario where CATALINA_HOME (tomcat installation) and CATALINA_BASE (webapp home) are not the same?

The relevant log line:

22-Jul-2018 20:36:29.504 INFORMATION [localhost-startStop-1] org.apache.catalina.startup.ContextConfig.getDefaultWebXmlFragment No global web.xml found

The complete startup log. The servlet "default" is not found because it is defined in the global web.xml. <my-app-dir> redacted by me.

22-Jul-2018 20:36:28.103 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Server version:        Apache Tomcat/8.5.27
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Server built:          Jan 18 2018 20:12:40 UTC
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Server number:         8.5.27.0
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log OS Name:               Linux
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log OS Version:            4.4.0-1062-aws
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Architecture:          amd64
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Java Home:             /a/java/jdk1.8_lin64/jre
22-Jul-2018 20:36:28.106 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Version:           1.8.0_162-b12
22-Jul-2018 20:36:28.107 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log JVM Vendor:            Oracle Corporation
22-Jul-2018 20:36:28.107 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_BASE:         /0/<my-app-dir>/tomcat
22-Jul-2018 20:36:28.107 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log CATALINA_HOME:         /a/servers/Tomcat8_lin64
22-Jul-2018 20:36:28.110 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.config.file=/0/<my-app-dir>/tomcat/conf/logging.properties
22-Jul-2018 20:36:28.111 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
22-Jul-2018 20:36:28.111 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.awt.headless=true
22-Jul-2018 20:36:28.111 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djdk.tls.ephemeralDHKeySize=2048
22-Jul-2018 20:36:28.111 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.protocol.handler.pkgs=org.apache.catalina.webresources
22-Jul-2018 20:36:28.112 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Xms256m
22-Jul-2018 20:36:28.112 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Xmx256m
22-Jul-2018 20:36:28.112 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dignore.endorsed.dirs=
22-Jul-2018 20:36:28.112 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.base=/0/<my-app-dir>/tomcat
22-Jul-2018 20:36:28.112 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Dcatalina.home=/a/servers/Tomcat8_lin64
22-Jul-2018 20:36:28.113 INFORMATION [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Djava.io.tmpdir=/0/<my-app-dir>/tomcat/temp
22-Jul-2018 20:36:28.619 INFORMATION [main] org.apache.coyote.AbstractProtocol.init Initializing ProtocolHandler ["http-nio-8780"]
22-Jul-2018 20:36:28.654 INFORMATION [main] org.apache.tomcat.util.net.NioSelectorPool.getSharedSelector Using a shared selector for servlet write/read
22-Jul-2018 20:36:28.671 INFORMATION [main] org.apache.catalina.startup.Catalina.load Initialization processed in 839 ms
22-Jul-2018 20:36:28.687 INFORMATION [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina]
22-Jul-2018 20:36:28.687 INFORMATION [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.27
22-Jul-2018 20:36:28.769 INFORMATION [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployWAR Deploying web application archive [/0/<my-app-dir>/tomcat/webapps/ROOT.war]
22-Jul-2018 20:36:29.504 INFORMATION [localhost-startStop-1] org.apache.catalina.startup.ContextConfig.getDefaultWebXmlFragment No global web.xml found
22-Jul-2018 20:36:29.806 SCHWERWIEGEND [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start: 
 org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:986)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalArgumentException: Servlet mapping specifies an unknown servlet name [default]
    at org.apache.catalina.core.StandardContext.addServletMappingDecoded(StandardContext.java:3155)
    at org.apache.catalina.core.StandardContext.addServletMappingDecoded(StandardContext.java:3145)
    at org.apache.catalina.startup.ContextConfig.configureContext(ContextConfig.java:1376)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1190)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:775)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5105)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 10 more

I don't understand the reason for this warning:

WARNING 0x0000: Referencing data in revision 6882, which is older than the oldest dumped revision (r7001). Loading this dump into an empty repository will fail.

I'm trying migrate an old repository to a new server via a dump/load cycle.

I thought this would be a good opportunity to get rid of some of the oldest revisions, so I used this command:

svnadmin dump -r7001:HEAD C:\svnrepo > C:\temp\repo.dmp

I was expecting the dump to collect all necessary "base info" into the first dumped revision. How can I get rid of the old revisions?

I cannot figure out how to disable authentication for the .well-known directory.

Things behave as expected when I remove the SVN specific directives (DAV, SVNPath, AuthzSVNAccessFile).

<VirtualHost *:443>
  ServerName www.example.com
  DocumentRoot "C:/www.example.com"
  ServerAdmin [email protected]

  SSLEngine On
  SSLCertificateFile "C:/Apache2/conf/ssl/www.example.com.crt"
  SSLCertificateKeyFile "C:/Apache2/conf/ssl/www.example.com.key"

  <Location />
    DAV svn
    SVNPath "C:/svnrepo"
    SSLRequireSSL 

    AuthName "www.example.com"
    AuthType Basic
    AuthUserFile "conf/svn/svn-users.txt"
    AuthGroupFile "conf/svn/svn-groups.txt"
    AuthzSVNAccessFile "conf/svn/svn-access.txt"

    Require valid-user
  </Location> 

  <Location "/.well-known">    
    Satisfy Any
    Allow from all
    Require all granted
    # Apache 2.4 only
    #AuthType None
  </Location>
</VirtualHost>

Edit: It would also work if I didn't have overlapping paths. E.g. using /svn and /.well-known. Unfortunately that is not something I can change easily now.

I'm planning to setup a Hyper-V virtual machine with Windows 10 and try to migrate some business applications. If everything works, I plan to activate with a Win 10 Professional license key. Unfortunately, I only see the Enterprise iso available for download.

Is it possible to switch the version later during activation?

Or can I get an official Professional evaluation ISO somewhere?