When one of your zookeeper nodes is sending you this message, that means that your Zookeeper cluster hasn’t started in the right order.
Solution: Restart your cluster (node per node), starting from node 1 (as stated in zoo.conf)
This problem is easy to diagnose. When the order was wrong you will get this output:
[myserver:myuser] ~: echo stat | nc localhost 2181
This ZooKeeper instance is not currently serving requests
After you’ve restarted all nodes (in the correct order), you will get this output:
[myserver:myuser] ~: echo stat | nc localhost 2181 |grep Mode
[myserver:myuser] ~: echo stat | nc localhost 2181 |grep Mode
Hope this will help you out!
It’s been a while since I’ve used Calibre to manage my Kindle, but today I wanted to transfer some PDF’s.
Unfortunately Calibre stopped working as soon as I tried to open a dialog window.
As it seems, Fedora has adopted a new display server, called Wayland. Since Calibre has dependencies in the previous adoption X-Server, Calibre won’t start.
In my case, the solution was to set a different GDK backend, before starting Calibre.
Open a terminal and enter the following command:
Okay, this has taken me too long to not post.. So here it is..:
When your firewall is blocking SSL traffic but allowing HTTP traffic, openssl s_client will show this:
my_host:joris [/etc/stores] openssl s_client -host external_host -port 12345
no peer certificate available
No client certificate CA names sent
SSL handshake has read 0 bytes and written 247 bytes
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Continue reading “Why no SSL!? Port is open!”
I was searching for this answer and couldn’t find it quickly, thus decided to create this post. I keep running into the nwtraders.msft hostnames because I’m using CentOS images in Vagrant.., to be precise; the london.nwtraders.msft hostname..
NWTraders is a fictional company, created by Microsoft to showcase Microsoft Access.
Continue reading “Who or what is nwtraders.msft?”
This is so simple it’s just great 🙂
Solution: use regex in your grep so the grep itself doesn’t show up in the results.
[vagrant@london kafka]$ ps aux |grep kafka
vagrant 5172 0.8 30.3 3178252 309428 ? Sl 07:00 0:06 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/var/log/kafka/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/var/log/kafka -Dlog4j.configuration=file:/etc/kafka/log4j.properties -cp :/usr/bin/../share/java/kafka/*:/usr/bin/../share/java/confluent-support-metrics/*:/usr/share/java/confluent-support-metrics/* io.confluent.support.metrics.SupportedKafka /vagrant/config/kafka0.properties
vagrant 5824 0.0 0.0 103316 836 pts/0 R+ 07:13 0:00 grep kafka <<-- Oh no!
[vagrant@london kafka]$ ps aux |grep [k]afka
root 5172 0.8 29.6 3178252 302472 ? Sl 07:00 0:04 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Xloggc:/var/log/kafka/kafkaServer-gc.log -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/var/log/kafka -Dlog4j.configuration=file:/etc/kafka/log4j.properties -cp :/usr/bin/../share/java/kafka/*:/usr/bin/../share/java/confluent-support-metrics/*:/usr/share/java/confluent-support-metrics/* io.confluent.support.metrics.SupportedKafka /vagrant/config/kafka0.properties
Okay, this is kinda awesome :-), I got my geek on 🙂
My application is connecting to a cluster of external servers but my application can configure hostname but can’t configure port.
So I wanted to connect to a remote cluster using SSH tunneling, but I was unable to forward everything because the port binding to localhost (127.0.0.1) can only be used once.
Then I saw that you can use multiple loopback addresses! See this page: https://en.wikipedia.org/wiki/Loopback
Basically you can bind the portforward to 127.0.0.2, 127.0.0.3 till 127.255.255.254, that should provide enough addresses, right!? 🙂
So I can use multiple port forwards from my localhost(s) to the six remote hosts like this:
ssh somedomain.com \
-L 127.0.0.1:9042:external-node1.somedomain.com:9042 \
-L 127.0.0.2:9042:external-node2.somedomain.com:9042 \
-L 127.0.0.3:9042:external-node3.somedomain.com:9042 \
-L 127.0.0.4:9042:external-node4.somedomain.com:9042 \
-L 127.0.0.5:9042:external-node5.somedomain.com:9042 \
Wow, talk about a crappy post title, but I just got this working on my corporate network and was quite happy about it.
Reason for this post; Every time I start a new assignment at a (rather big) corporation, I need to follow these steps to be able to access the internet from my vm’s.
(and I keep forgetting the steps, I’m getting old..)
What we’ll use to get this working:
- Cygwin : https://www.cygwin.com/
- Vagrant : https://www.vagrantup.com/
- Virtualbox : https://www.virtualbox.org/
- Cntlm : http://cntlm.sourceforge.net/
I’m running CentOS vm’s inside Vagrant with Virtualbox provisioning on Cygwin on Windows 7. I’m running Cntlm to create a local proxy for all stuff what I’m doing through cygwin, because I don’t like putting clear text passwords in bashrc or in Win / Bash variables.
- Get your corporate proxy URL (Via Google Chrome)
- Configure Cntlm
- Configure Cygwin
- Configure Vagrant
- Use teh interwebs from your VM, practicing ninja turtle coding skillz and be instantly awesome!!1!
Continue reading “Vagrant proxy through CNTLM on Windows using CYGWIN”
I’ve been struggling to get Fedora working on my new laptop (Dell XPS 13 Skylake 9350) since I got it a couple of months ago. It was quite frustrating to have a working LiveCD (LiveUSB) but my laptop kept failing to boot Fedora.
Today I’ve found the problem and the fix was easy.
After the installation the EFI boot partition contains a fedora directory
Contents of the fedora directory:
│ └── unicode.pf2
├── shim.efi <<<< This is the one!!
The solution was to create a new Boot entry in the BIOS, this wasn’t done automatically by Fedora.
Configure the UEFI boot manager to point to the shim.efi file.
When that’s done, reboot your laptop and start using Fedora.
I encountered this error last week and it was quite a headache to find out what the source of the problem was.
I thought the BEA-010213 error and the rollback log entries meant that we had a database problem. This was a wrong assumption, there’s another storage type in weblogic domains which use transactions (or state transitions?), which are JMS queues, which live in persistent stores in the managed servers.
That was the source of our problem; our persistent stores became corrupted because of storage problems.
Continue reading “BEA-010213, Message-Driven EJB: MyProcessMDB's transaction was rolled back”
I’ve been quite busy this whole day with a partially complete database dump and wanted to prepare for tomorrow with some ninja bash voodoo shizzle. I’m doing a braindump here because I know I’ll have forgotten this when I wake up tomorrow 🙂
The command stated below was the first working example I’ve gotten together, please let me know if you know a neater / better solution!
I’ve got two files. The first file contains lines which need to be deleted from the second line (if they exist there) Continue reading “Remove duplicate lines while comparing two files”