Docker: Networking with docker swarm: creating new subnets/gateways/…

In this posting i explained how to configure the network for a container on a docker machine.
If you want to do this for a docker swarm, you have to change the commands. The network driver "bridge" does not work in swarm mode:
(How to run a container inside a swarm take a look here)

docker service create  --network mybrigde --name helloworld alpine ping

Error: No such network: mybrigde
Even (more...)

Docker: Network configuration: How to customize the network bridge and use my own subnet / netmask / CiDR

In my last posting i described how to configure the network settings of a container via docker command line:
--net none
--net bridge
Now i want to try to change the subnet from the standard to another ip range.

There are some tutorials out there which say:

docker run -it  --net bridge  --fixed-cidr ""  alpine /bin/ash
unknown flag: --fixed-cidr
but this doesa not work any more.

First you (more...)

Docker: Network configuration – none / brigde / hostname / dns entries

If you are starting your docker container you can add some network configuration details via command line.
Let's start with the easiest network setting:
docker run -it  --net none alpine /bin/ash
This setting starts the container without any connectivity to the network:
# ip addr show
1: lo: mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet scope host lo
       valid_lft forever preferred_lft forever

Docker: How to limit memory

By starting your container you can limit the RAM usage simply by adding
-m 4M

(this limits the memory to 4 megabytes).

To check this simply run:

docker run -it -m=4M  --rm alpine /bin/ash

and on your docker machine check the following entry:

alpine:~# cat /sys/fs/cgroup/memory/docker/4ce0403caf667e7a6d446eac3820373aefafe4e73463357f680d7b38a392ba62/memory.limit_in_bytes 

Docker: Lessons learned – Logging

After some time working with docker here my experiences:

Some days ago i created my own container with a minimal web service.

Here the
sed -i  's/Hostname:.*/Hostname: '$HOSTNAME'/g' index.html
while true; do { echo -e 'HTTP/1.1 200 OK\r\n'; cat index.html;}  | nc  -l -p 8080  2>&1 >> logfile; done
This is the Dockerfile:
FROM alpine


RUN mkdir ncweb

ADD .  /tmp

ENTRYPOINT [ "/tmp/" (more...)

Virtualbox: failed & Run ‘make oldconfig && make prepare’

After updating to ubuntu 18.04 i had to reinstall virtualbox:

# dpkg -i virtualbox-5.2_5.2.10-122088~Debian~stretch_amd64.deb 
Vormals nicht ausgewähltes Paket virtualbox-5.2 wird gewählt.
(Lese Datenbank ... 378316 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von virtualbox-5.2_5.2.10-122088~Debian~stretch_amd64.deb ...
Entpacken von virtualbox-5.2 (5.2.10-122088~Debian~stretch) ...
virtualbox-5.2 (5.2.10-122088~Debian~stretch) wird eingerichtet ...
addgroup: Die Gruppe »vboxusers« existiert bereits als Systemgruppe. Programmende. failed: Look at /var/log/vbox-install. (more...)

Running RAC in a Virtual Environment

I was in a discussion at an Oracle Meetup this week, and the subject of RAC in a virtualized environment – specifically Oracle Virtual Machine (OVM) – came up.
Here’s a couple of points which were discussed.


There was a lack of awareness of a common problem, which has a solution built-in to Oracle Grid Infrastructure and later. In a virtualized environment, the network components are also virtualized. Sometimes, network (more...)

Playing with Oracle Ravello – Migrating your VMs to the Cloud

Hello everyone, A few years back we had the boom of the “Private Cloud” rush, where everyone started to implement virtualization technologies to make a better use of it Infrastructure resources and improve high availability, scalability and innovation! Now to

Oracle VM Server: How to add ISO images to your repository

After  setting up
you have to upload some ISO images to your repository, so that your virtual machines can boot with these ISO images.

So inside Oracle VM Manager go to the "Repositories" tab and use the "import iso icon" (the blue arrow):

The only way to import ISO images is to give a URL to Oracle (more...)

Oracle VM Server: my first vm: Error: HVM guest support is unavailable

All my tests with Oracle VM Server are running inside Oracle Virtualbox. If you want to do some tests yourself with this setup, you can easily get this error message after powering on your VM:

Server error: Command: ['xm', 'create', '/OVS/Repositories/0004fb0000030000dad74d9c43176d2e/VirtualMachines/0004fb00000600005e79798ecb1a63cf/vm.cfg'] failed (1): stderr: Error: HVM guest support is unavailable: is VT/AMD-V supported by your CPU and enabled in your BIOS?
stdout: Using config file "/OVS/Repositories/0004fb0000030000dad74d9c43176d2e/VirtualMachines/0004fb00000600005e79798ecb1a63cf/vm.cfg".
To get your system running, you have (more...)

Docker: How to build you own container with your own application

atThere are many tutorials out there, how to create a docker container with a apache webserver inside or a nginx.
But you can hardly find a manual how to build your own docker container without pulling everything from a foreign repository.
Why should you not pull everything from foreign repositories?

You should read this article or this:
But since each phase of the development pipeline is built at a different time, …
…you can’t (more...)

Oracle VM Server x86: Creation of a virtual machine

After all these steps
it is possible to create a VM:

 Click the third icon:

And here is the summary:
One thing still missing: I did not put an ISO image into the repository, so this VM has no media to start from. The Import of an ISO image i will post in a week.

Oracle VM Server: supported guest systems

After the installation of


the next step is to install a guest. But which operating systems are supported on Oracle VM Server?
Let's look into the official Oracle documentation:
The list of supported operating systems can be found here.

Table 5.1 HVM-Supported Linux Guest Operating Systems
Guest Operating System
HVM 32-bit
HVM 64-bit
Oracle Linux Release 7.x
Oracle Linux Release 6.x
Oracle Linux (more...)

Docker-CE: How to modify containers with overlays / How to add directories to a standard docker image

After some experiments with docker i wanted to run a tomcat with my own configuration (e.g. memory settings, ports, ...).

The first guess is: Download tomcat, configure everything and then build an image.
BUT: After i learned how to use the -v (--volume) flag for adding some file via the docker command to an image i was wondering, wether creating a new image with only the additional files on top of standard (more...)

#DOAG2017 wrap up


Another DOAG is over and here are my summary.

Day 1

As my presentation is planned for noon I arrived this year on the evening before, so I could attend the early sessions on 8:30.

Sten Vesterli: APEX, ADF, or ABCS? A real-life application built in 3 tools

He compares the development of a real application in APEX, ADF and ABCS. He don’t believe that ABCS is usable from end users and shows interesting (more...)

PeopleSoft and Docker’s value proposition

If you haven't heard yet about Docker and/or container technologies, you will soon do. Docker has made one of the biggest impacts in the IT industry in 2014. Since the release of its 1.0 version on past June, it has captured the attention of many big IT vendors, including Google, Microsoft and Amazon. As far as I'm aware, Oracle has not announced any initiative with Docker, except for the Oracle Linux container. Still, Docker (more...)

My Presentation on Oracle Solaris Zones Capacity Management

So one more successful annual conference of All India Oracle Users Group (AIOUG) happened on November 9th and 10th at Hyderabad, India.

Earlier I used to attend Oracle database sessions at AIOUG but this time AIOUG board had done a remarkable job by extending the coverage to Solaris topics. Obviously as (more...)

Build an 11gR2 RAC cluster in VirtualBox in 1 Hour using OVM templates

[I originally posted this over at the Pythian blog. If you're not following it, you should! Way more content, by far smarter people than lil ol' me.]

After reviewing my blog post about running EBS OVM templates in VirtualBox, two of my teammates suggested that I work on something with potentially broader appeal. Their basic message was, "This is really cool for us EBS nerds, but what about the Core DBAs?"

So how does "11gR2 RAC in an hour" sound? :-) In this post, I'll demonstrate how to deploy the pre-built Oracle VM templates to create a two-node (more...)

Build an E-Business Suite 12.1.3 sandbox in VirtualBox with one hour of work

[I originally posted this over at the Pythian blog. If you're not following it, you should! Way more content, by far smarter people than lil ol' me.]

Self-directed learning about a product as complex as Oracle E-Business Suite can be challenging. Oracle helpfully provides a pre-built environment (called 'Vision') for training purposes. Configuring a viable training or "sandbox" environment on a workstation can be pretty daunting, however, considering:

  1. The memory and storage resources required to run a "small" Vision instance
  2. The need to install and configure the OS and a list of pre-requisite patches and packages
  3. Learning about the (more...)

Oracle Throws in the Towel on VMware Licensing – Reprise

Given the incredible number of comments I received on my last blog post, and the content of those comments, it is very obvious that folks are extremely confused by what I meant by that post, as well as the comments by Mr. Garsthagen (Oracle Director Level Employee), referenced in that post.

The confusion is typified by the following comment, the most recent I have received:

Oracle does not recognize either (Vmware/DRS Affinity) as a hard partition

First, to be completely clear, I have never stated, nor do I believe, that VMware (or any other software hypervisor for that matter) (more...)