apt-get install aspnetcore-runtime-2.2 fails on ubuntu: workaround with snap

Two week ago i tried to install a microsoft tool on my linux laptop and i got the following error:
So i tried:

apt-get install aspnetcore-runtime-2.2
Paketlisten werden gelesen... Fertig
Abhängigkeitsbaum wird aufgebaut.
Statusinformationen werden eingelesen.... Fertig
Einige Pakete konnten nicht installiert werden. Das kann bedeuten, dass
Sie eine unmögliche Situation angefordert haben oder, wenn Sie die
Unstable-Distribution verwenden, dass einige erforderliche Pakete noch
nicht erstellt wurden oder Incoming noch nicht verlassen haben.
Die (more...)

Ubuntu Server: How to activate kernel dumps

If you are running ubuntu server, you can add kdump on your system to write kernel dumps in case of sudden reboots etc.

Installing is very easy:
root@ubuntuserver:/etc# apt install linux-crashdump
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following additional packages will be installed:
  binutils binutils-common binutils-x86-64-linux-gnu crash kdump-tools kexec-tools libbinutils libdw1 libsnappy1v5 makedumpfile
Suggested packages:
  binutils-doc
The following NEW packages will be installed:
  binutils binutils-common binutils-x86-64-linux-gnu (more...)

Google Jamboard ?!

By reorganising my Google drive i ran into "Jamboard"...
This is a tiny Google web application, where you can do some fast sketches but the functionality is really limited:








Ubuntu Server: eBook

For testing waagent (Microsoft Azure Linux Guest Agent) i downloaded Ubuntu Server. Ubuntu advertised an ebook for administrators:

Here the short summary from this webpage:

Server provisioning: what Network Admins and IT pros need to know

This document is designed to help system administrators and DevOps focused organisations to understand bare metal server provisioning, understand its value proposition, and learn about how leading companies are using server provisioning solutions within their hyperscale environments.
Canonical’s (more...)

Oracle JDeveloper: Is this IDE dead? Are there new releases?

Some weeks ago i read the Java Magazine (http://www.javamagazine.mozaicreader.com)

They report from a survay taken place in 2018 about Java. One of the questions was which application server do you use in production:

This was not really amazing.
But the question about the IDE gave a really surprising result:



More developers use IntelliJ than Eclipse?
Not really surprising was the usage of Oracle's JDeveloper: Only 1% of the developers (more...)

Wireguard: Status information / using the wg command


After the installation of wireguard on two servers i shut down the secondary server and after 4h i did the wg command:
root@zerberus:~# wg
interface: wg0
  public key: XXX=
  private key: (hidden)
  listening port: 46932

peer: YYY=
  endpoint: 192.168.178.54:35891
  allowed ips: 10.0.0.2/32
  latest handshake: 4 hours, 19 minutes, 2 seconds ago
  transfer: 348 B received, 436 B sent
With the "ip addr" (more...)

firefox extension do not work anymore….

Today some of my extensions stopped to work and a reinstall failed due to "Download failed. Please check your connection.":

There is an article about this issue, which says, that this is due to an expired certificate:
https://www.bleepingcomputer.com/news/software/firefox-addons-being-disabled-due-to-an-expired-certificate/

The workarounds stated there, do not work for my extensions, so i have to wait, that firefox gets a solution (and a new certificate).

For all others with this problem: Do not deinstall your (more...)

Wireguard: Installation & configuration

To install wireguard i followed this instruction.
First step is to add the repository to your machine:

root@zerberus:~# add-apt-repository ppa:wireguard/wireguard
 WireGuard is a novel VPN that runs inside the Linux Kernel. This is the Ubuntu packaging for WireGuard. More info may be found at its website, listed below.

More info: https://www.wireguard.com/
Packages: wireguard wireguard-tools wireguard-dkms

Install with: $ apt install wireguard

For help, please contact

Review at amazon: SAP Cloud Platform

Last week i read this book:
Before starting with the Oracle Cloud i wanted to read something other than AWS or Microsoft Azure. I was surprised at the completely different target of this cloud in respect to AWS and Azure. It is much more focused on business and business value - which is clearly one core domains of SAP.

This book contains a very well written introduction into cloud services - many other books could (more...)

Oracle Database 19c (19.3) released!

And after nearly 3 months of waiting - Oracle released 19c:


First special feature: The rpm is still there and the release is only done for Linux and Oracle Solaris.

To get to the Linux download page just click here.



But the Grid Infrastructure is still not delivered as RPM package. :-(


Wireguard: An easy way to build VPNs

Last week i came across the following tool:

If you want to build up a VPN you can choose one of the following strategies:
  • based on IPSec
  • using TLS
(These two are the options to choose - of course there are some others...)

The nice thing with wireguard (from the linux point of view) is, that the wireguard interfaces are handled like all other  network interfaces on your device.

If you (more...)

Oracle VM Server: Working with ovm cli

After getting the ovmcli run, here some commands which are quite helpful, when you are working with Oracle VM server.
But first:
Starting the ovmcli is done via
ssh admin@localhost -p 10000
at the OVM Manager.

After that you can get some overviews:
OVM> list server
Command: list server
Status: Success
Time: 2019-01-25 06:56:55,065 EST
Data:
  id:18:e2:a6:9d:5c:b6:48:3a:9b:d2:b0:0f:56:7e:ab:e9  name:oraclevm
OVM> list vm
Command: list vm
Status: Success
Time: 2019-01-25 06:56:57,357 EST
Data:
  id:0004fb0000060000fa3b1b883e717582  name:myAlpineLinux
(more...)

Oracle Database 19c download

In january 2019 Oracle released the documentation for Oracle Database 19c.

More than 7 weeks later there is still nothing at https://www.oracle.com/downloads/:


The gap between release date of the documentation and the on premises software was for 18c not so long...

Will 19c on premises software be released before may? Or later in summer?

AWS: Accessing S3 buckets from the internet and from ec2 instances (2)

After accessing a S3 bucket from an ec2 instance by adding an IAM role to my EC2 instance, i tried to get the access from an ec2 instance by using a AWS endpoint.

First step: Launch an ec2 instance within your VPC and try to access your S3 bucket:

[ec2-user@ip-172-31-30-93 ~]$ wget https://s3-eu-west-1.amazonaws.com/my.webtest/website.json
--2019-02-02 18:29:28--  https://s3-eu-west-1.amazonaws.com/my.webtest/website.json
Auflösen des Hostnamen »s3-eu-west-1.amazonaws.com (s3-eu-west-1.amazonaws.com)«... 52.218. (more...)

Oracle VM Server: OVM CLI via ssh admin@localhost -p 10000 does not work


In my Oracle VM server installation the ovmcli refuses to work:
ssh -l admin localhost -p 10000 

Connection to localhost closed by remote host.

Connection to localhost closed.
There some workarounds like:
ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 -oHostKeyAlgorithms=+ssh-dss -l  admin localhost -p 10000
But the result is the same.

Here a debug output from ssh -v:
[root@oraVMManager mnt]# ssh -l admin localhost -p 10000  -v
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017
debug1: Reading configuration data (more...)

review at amazon: Azure for Architects

This weekend i read "Azure for Architects - Implementing cloud design, DevOps, containers, IoT and serverless solutions on your public cloud".


After i had some trouble to publish my review on amazon.de and i put in onto my blog (take a look here), i wrote a smaller review only about 2 chapters. And this worked...

One statement i liked, was:
This is not only true for security, but sometimes it is important to (more...)

AWS: overview of all postings

After nearly an half year of looking into AWS, here a summary of all postings related to that topic:
ECS & S3 (Computing & Storage):

Microsoft Azure: Adding user requires more work as expected

Just to try some things in Microsoft Azure i wanted to add an additional user to my test account. But this was not so easy:

Go to "Azure Active Directory" and "Users":

 

 But then:

I thought this is not really a problem, because openesb.eu is my domain, so let's try to verify this one:


The problem is, that i am not able to change this settings. So i tried, if i am lucky, (more...)

Microsoft Azure: How to use waagent (Microsoft Azure Linux Agent)

After installation waagent on my ubunu server, i tried to use this tool.
First guess was to read the manpages, but there is no entry for waagent:
root@ubuntuserver:~# man waagent
No manual entry for waagent
See 'man 7 undocumented' for help when manual pages are not available.
So for documentation you have to visit the Microsoft Azure portal:
https://docs.microsoft.com/en-us/azure/virtual-machines/extensions/agent-linux



Here are some commands i tried:
root@ubuntuserver:~# waagent -show-configuration
AutoUpdate.Enabled = True
AutoUpdate. (more...)

review: architecting microsoft azure solutions

Last week i read the exam ref "architecting microsoft azure solutions"

The book cover states
Designed for architects and other cloud professionals ready to advance their status, Exam Ref focuses on the critical thinking and decision-making acumen needed for success at the MCSA level.
The book "Architecting Microsoft Azure Solutions" comes with 320 pages and 6 chapters. The claim of the book: "This book teaches you how to design and architect secure, highly-available, performant, monitored (more...)