Setting up ELK

elasticsearch (elastic licence, with builtin JAVA)

wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.9.0-amd64.deb
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.9.0-amd64.deb.sha512
shasum -a 512 -c elasticsearch-7.9.0-amd64.deb.sha512

kibana (elastic licence)

wget https://artifacts.elastic.co/downloads/kibana/kibana-7.9.0-amd64.deb
wget https://artifacts.elastic.co/downloads/kibana/kibana-7.9.0-amd64.deb.sha512
shasum -a 512 -c kibana-7.9.0-amd64.deb

logstash (elastic licence, require Java 8)

wget https://artifacts.elastic.co/downloads/logstash/logstash-7.9.0.deb
wget https://artifacts.elastic.co/downloads/logstash/logstash-7.9.0.deb.sha512
shasum -a 512 -c logstash-7.9.0.deb.sha512

elasticsearch (apache2 licence, no Java)

remember to set JAVA_HOME

wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-oss-7.9.0-no-jdk-amd64.deb
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-oss-7.9.0-no-jdk-amd64.deb.sha512
shasum -a 512 -c elasticsearch-oss-7.9.0-no-jdk-amd64.deb.sha512

kibana (apache2 licence, no Java)

wget https://artifacts.elastic.co/downloads/kibana/kibana-oss-7.9.0-amd64.deb
wget https://artifacts.elastic.co/downloads/kibana/kibana-oss-7.9.0-amd64.deb.sha512
shasum -a 512 -c kibana-oss-7.9.0-amd64.deb.sha512

logstash (apache2 licence, no Java)

wget https://artifacts.elastic.co/downloads/logstash/logstash-oss-7.9.0.deb
wget https://artifacts.elastic.co/downloads/logstash/logstash-oss-7.9.0.deb.sha512
shasum -a 514 -c logstash-oss-7.9.0.deb.sha512

installing elasticsearch

dpkg -i elasticsearch-7.9.0-amd64.deb
sudo systemctl status elasticsearch.service
sudo systemctl start elasticsearch.service

installing kibana

dpkg -i kibana-7.9.0-amd64.deb
sudo systemctl status kibana.service
sudo systemctl start kibana.service

installing logstash

dpkg -i logstash-7.9.0.deb
echo ‘LS_OPTS=”-w 2″‘ >> /etc/defaults/logstash
sudo systemctl status logstash.service
sudo systemctl start logstash.service

Will human transplants change biometrics?

https://sg.style.yahoo.com/transplant-patients-dna-is-replaced-with-that-of-his-donor-124035642.html

9 December 2019

A transplant patient developed the DNA of his donor, it has emerged.

Chris Long, from Reno in Nevada, had a blood test three months after receiving a bone marrow transplant.

Results revealed his DNA had been “replaced” by that of his donor, a German man 10 years his junior.

Four years later, the donor’s genetic material was found in Mr Long’s cheeks, lips and semen. While levels fluctuated over time, only his chest and head hair were unaffected.

HTTPS and Geolocation with web browsers

I’ve starting coding apps to get a javascript geolocation refresher. Switching between OSX and W10 was quite a pain because:

  1. Safari does not support geolocation over HTTP (no idea why http://localhost/ is considered an issue with Safari).
  2. W10 Edge supports geolocation over HTTP.

After some experimenting, I discovered Chrome and Brave both support geolocation over HTTP on OSX. Chrome definitely was doing WiFi triangulation because it could return my exact lat/lng whereas Brave was returning the midtown lat/lng coordinates.

Problems starting Eclipse after updating JDK on OSX

I came across this problem when updating jdk via brew. Somehow brew removed openjdk-12 and replaced it with 14. Pesky.

After some checks, I figured the Eclipse 2020-06 executable was relying on a hardcoded openjdk path.

To rectify this, I’ve done the following:

  1. Determine the jvm available on osx by dropping to command line and running ‘/usr/libexec/jvm_home -V’

Below is a screen capture of the available openjdks on my OSX. (openjdk-12 was removed somehow). Remember the location of the openjdk directory you wish to use.

2. Edit the openjdk path in eclipse.ini. The path to eclipse.ini is as follows:

Note: I have mine in $HOME/eclipse/java-2020-06. Yours could be in the Applications directory (ie /Applications/Eclipse)

Run ‘nano eclipse’

3. To get this:

eclipse.ini pointing to missing openjdk-12 folder

4. Amend the folder name to the openjdk directory that you’ve determined in Step 1.

I’ve selected openjdk-14.0.2.jdk

5. Ready to start Eclipse by running the eclipse executable.

Adjust Time Machine backup frequency

I managed to get a oldish 3Tb Time Capsule off Carousell for experimenting. It was pretty alright for the first day until I got tired of the hourly loudish HDD spin up.

There must be a way to adjust the hourly backup frequency to every 6 hours. Given this is a oldish EOLed device, I also want to preserve its longevity – as much as i can.

To do so, determine the new backup frequency you want it to be, knowing the backup daemon reads in the backup frequency in seconds.

If you want to adjust to a 12 hour backup, the new number would be 60 seconds * 60 minutes * 12 hours = 43,200

For a 6 hour backup frequency, the new number would be 60 seconds * 60 minutes * 6 hours = 21,600

Next,

  1. Go to the macOS terminal app and do the following:
  2. Unload the backup daemon using “sudo launchctl unload /System/Library/LaunchDaemons/com.apple.backupd-help.plist
  3. Change frequency on the the following file /System/Library/LaunchDaemons/com.apple.backupd-helper.plist using “sudo nano /System/Library/LaunchDaemons/com.apple.backupd-helper.plist
  4. Look for the line that says “<key>Interval</key><integer>3600</integer>“, change the integer value to the newly calculated value above without the comma.
  5. It should read the following with a 12 hour backup frequency “<key>Interval</key><integer>43200</integer>
  6. Save the file with Ctrl-X.
  7. Then reload the plist using “sudo launchctl load /System/Library/LaunchDaemons/com.apple.backupd-help.plist

You will only hear the HDD storage startup only twice a day, and extend the HDD’s life!

PS – The above was verified to work on Mojave.

PPS – You will need to do this for every macOS device.

Another good reason for using macOS (Resetting router password)

I got stuck resetting a router’s administrative password. While I had the required Cisco cable (console to serial) and a Usb to Serial adapter, Windows 10 wasn’t too happy with the Usb to Serial adapter I had.

Windows 10 said the Usb to Serial adapter was too old and wanted me to “CONTACT THE DEVELOPER”. No kidding, that’s what was written on the Devices page.

Switching to the MBP, I connected the Usb end of the Usb – Serial cable and did a

screen /dev/tty.usbserial

And I got a response from the router immediately.