Working around Docker’s download limit on RedHat OpenShift

Taken from “How to work around Docker’s new download rate limit on Red Hat OpenShift” from RedHat Developer.

Docker recently changed its policy for downloading images as an anonymous user. The company now has a limit of 100 downloads every six hours from a single IP address.

If you are using the OpenShift Developer Sandbox to experiment with a free OpenShift cluster, you might encounter the error message shown in Figure 1.

All you have to do to avoid Docker’s new rate-limit error is authenticate to your Docker Hub account. After you’ve authenticated to the account, you won’t be pulling the image as an anonymous user but as an authenticated user. The image download will count against your personal limit of 200 downloads per six hours instead of the 100 downloads shared across all anonymous cluster users.

For the complete article, do take a look at “How to work around Docker’s new download rate limit on Red Hat OpenShift” from RedHat Developer.

How to uninstall Centrify agent on Unix/Linux platforms?

As root or sudo, open a terminal and navigate to the folder where Centrify was first installed (typically /usr/share/centrifydc/bin) . On most Centrify DirectControl-managed systems, you can remove the Centrify DirectControl Agent and related files by running the uninstall.sh script.
as follows:

/bin/sh /usr/share/centrifydc/bin/uninstall.sh

For example:

Do you want to uninstall the CentrifyDC-5.8.1 package from this computer? (Q|Y|N) [N]:N

References

KB-1780: How to uninstall Centrify agent on Unix/Linux platforms?

Resolving r.Java is not found (attached, “rJavaError”) on R-4.1.0

If you are installing rJava in R and you encountered this issue during install

% R
> install.packages("rJava")
checking whether setjmp.h is POSIX.1 compatible... yes
checking whether sigsetjmp is declared... yes
checking whether siglongjmp is declared... yes
checking Java support in R... present:
interpreter : '/usr/bin/java'
archiver    : ''
compiler    : ''
header prep.: ''
cpp flags   : ''
java libs   : ''
configure: error: Java Development Kit (JDK) is missing or not registered in R
Make sure R is configured with full Java support (including JDK). Run
R CMD javareconf
as root to add Java support to R.

If you don't have root privileges, run
R CMD javareconf -e
to set all Java-related variables and then install rJava.

ERROR: configuration failed for package ‘rJava’
* removing ‘/usr/local/R-4.1.0/lib64/R/library/rJava’

The downloaded source packages are in
        ‘/tmp/RtmpnllvN9/downloaded_packages’
Updating HTML index of packages in '.Library'
Making 'packages.html' ... done
Warning message:
In install.packages("rJava") :
  installation of package ‘rJava’ had non-zero exit status
> install.packages("javareconf")
Warning message:
package ‘javareconf’ is not available for this version of R

The Issue is to fix the missing Java Support to R. You can download the Java version you required https://www.oracle.com/java/technologies/downloads/archive/ I chose version 11. I used the “Linux x64 Compressed Archive”. Installation was a breeze as it is just unpacking and java can be used immediately. But it is important to make sure the environment is fixed. For example,

export JAVA_HOME=/usr/local/jdk-11.0.12
export PATH=$PATH:/usr/local/jdk-11.0.12/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/jdk-11.0.12/lib
export MANPATH=$MANPATH:/usr/local/jdk-11.0.12/share

Now you can run R. At the command prompt, type install.packages(“rJava”)

% R
> install.packages("rJava")
> library("rJava")

References:

  1. Installing the rJava package

What is Digital Twin?

This article is taken from What is a digital twin? A real-time, virtual representation

Digital twins are real-time, virtual representations of objects, processes, and systems. While digital twins can represent purely digital things, they most frequently serve as a bridge between the physical and digital domains. For example, a digital twin could provide a digital view of the operations of a factory, communications network, or the flow of packages through a logistics system.

“The implementation of a digital twin is an encapsulated software object or model that mirrors a unique physical object, process, organization, person, or other abstraction,” according to Gartner. “Data from multiple digital twins can be aggregated for a composite view across a number of real-world entities, such as a power plant or a city, and their related processes.”

What is a digital twin? A real-time, virtual representation

curl: (28) Resolving timed out after 5515 milliseconds

If you encounter an error like curl: (28) Resolving timed out after 5515 milliseconds

[user1@hpc-node1 ~]# curl -fsS https://dlang.org/install.sh | bash -s dmd
curl: (28) Resolving timed out after 5515 milliseconds
curl: (28) Resolving timed out after 5512 milliseconds
curl: (28) Resolving timed out after 5514 milliseconds
curl: (28) Resolving timed out after 5513 milliseconds
curl: (28) Resolving timed out after 5514 milliseconds
curl: (28) Resolving timed out after 5514 milliseconds
curl: (28) Resolving timed out after 5515 milliseconds
curl: (28) Resolving timed out after 5514 milliseconds
curl: (28) Resolving timed out after 5515 milliseconds
curl: (28) Resolving timed out after 5515 milliseconds

It is likely a DNS Lookup Resolution Issue. You might want to take a look at /etc/resolv.conf . you may want to change the DNS to another nameserver that resolves faster like one from Google Public DNS IP Addresses

# Generated by NetworkManager
nameserver 192.168.0.1

To another nameserver, maybe like Google Public DNS IP Addresses. You can find more information at https://developers.google.com/speed/public-dns/docs/using

# Generated by NetworkManager
nameserver 8.8.8.8
nameserver 8.8.4.4

Apache Log4j Zero-Day Vulnerability

Taken from https://www.lunasec.io/docs/blog/log4j-zero-day/

What is Apache Log4j Zero-Day Vulnerability?

Apache Log4j has a serious unauthenticated Remote Code Execution (RCE) vulnerability which was just disclosed. The exploit code for this has also been released, and the vulnerability is actively exploited in the wild. By crafting a special string that is passed to the application/service log via Log4j, attackers can execute arbitrary code loaded from remote servers. This can potentially lead to a complete compromise of the server.

What versions are vulnerable?

Any software using Apache Log4j (as a component) version between 2.0 and 2.14.1, inclusive.

What do I need to do?

A. Servers running custom Java application/services

  1. If your Log4j version is vulnerable, install the latest patched version log4j-2.15.0-rc2 available on GitHub at https://github.com/apache/logging-log4j2/releases/tag/log4j-2.15.0-rc2.

B. Servers running Commercial off-the-shelf (COTS) products

  1. Plese refer to https://gist.github.com/SwitHak/b66db3a06c2955a9cb71a8718970c592 for a list of advisories from the major vendors and follow the advisory.

How can I check if I have been hacked/compromised?

Check your applications’ log files for strings resembling “jndi:ldap”.

For more information

See https://www.lunasec.io/docs/blog/log4j-zero-day/