Kev's Development Toolbox

November 8, 2015

Setting a root password for a Docker image created with USER

If you have a Docker image created with a non-root user using USER in your Dockerfile, but you need to su to root to install or update something owned by root, without setting a root password you won’t be able to su to root.

Instead, add a password for root in your Dockerfile (this is described here):

RUN echo "root:Docker!" | chpasswd

This is probably not a good idea for security reasons (especially if you are sharing your Dockerfile), but I needed to create something in a container to reuse when creating other new containers, so did this one-time to get the file I needed and then reused the file in containers with another image without the root user/password.

November 8, 2015

Running Weblogic 10.3 config utils in console mode, and gui mode in a Docker container

Most of Weblogic’s config utilities can run in a console/text mode if you need to run them from a terminal session in text mode, by passing the option: -mode=console

E.g. the apps here: /[middlewarehome]/wlserver_10.3/common/bin, like config.sh will run in console mode.

config_builder.sh however does not, and only runs in gui mode. This is an issue if you’re running Weblogic in a Docker container. All is not lost however, as you can forward X out of a Docker container, but it takes a few steps to get running.

Follow the steps in this logged issue to install and run socat, and then pass ‘-e DISPLAY=192.168.99.1:0’ where the IP address is the address of the vbox interface. On my Mac this looked like:

socat TCP-LISTEN:6000,reuseaddr,fork UNIX-CLIENT:\"$DISPLAY\"

then:

docker run -it -e DISPLAY=192.168.99.1:0 imageid bash

My image included xterm and dependencies installed via the Dockerfile with:

RUN yum install -y xterm

When attempting to run config.sh in gui mode however, it gave me this error:

Unable to instantiate GUI, defaulting to console mode.

This is fine for config.sh at it runs in console mode, but since config_builder.sh does not, it must run in gui mode with forwarded XWindows.

This post on ServerFault held the key – you need to also install libXtst:

yum install libXtst

Now all the utils will run in GUI mode forwarding X to your host. On Mac OS X this assumes also that you have XQuartz installed too.

November 8, 2015

Weblogic Portal 10.3.6 generic installer on Mac OS X – Insufficient Disk Space error

Trying to use the portal103_generic.jar installer on Mac OS X 10.11.1 gives this error even though you have plenty of free space:

A quick Google turns up this question and answer. Quick fix, run passing this option: -Dos.name=unix, so:

java -Dos.name=unix -jar portal103_generic.jar

Although others reported this avoided the issue, I then got this issue instead:

Exception in thread "chmodFile" java.lang.Error: Unix is not a supported OS platform.

 at java.lang.UNIXProcess$Platform.get(UNIXProcess.java:164)

Following additional suggestion here, using -Dspace.detection=false instead avoided the issue.

November 3, 2015

Creating a branch from a prior commit on GitHub

I was searching around for a while on how to create a new branch from a prior commit in the history on GitHub, and it’s actually supported within the web ui. See here for answer on SO with steps.