Wednesday, 9 December 2020

ElasticSearch 7.x not working after upgrade

In case you have upgraded elastic search by mistake and want to rollback to the previous working version, here are the steps.

In my case, I upgraded the ElasticSearch to 7.9.2-1 and wanted to rollback to 7.6.2-1

1. yum downgrade elasticsearch-7.6.2-1

2. Restart elasticsearch

sudo service elasticsearch start

I hope it will work but in case you are facing any of the following issues, please run respective comments.


Problem. Unable to create temporary keystore at [/etc/elasticsearch/elasticsearch.keystore.tmp]

Solution: sudo -u elasticsearch -s /usr/share/elasticsearch/bin/elasticsearch-keystore create

Problem: Likely root cause: java.nio.file.AccessDeniedException: /etc/elasticsearch

Solution: chmod g+w /etc/elasticsearch

Thanks!! Enjoy Programming!

Reference Links


Monday, 28 September 2020

SSL(Self-Signed) Certificates are working fine on Firefox and Safari, but not on Chrome

Yesterday, I implemented self-signed SSL certificates to one of my websites, and to my surprise https link was working as expected on Safari and Firefox, but not on the Chrome browser. I was getting the following error:

With this, I connected with my IT team and come to know that, the certificates are not generated properly. All the browsers support different SSL expiry dates and we had to raise requests again to generate SSL Certificates for a minimum duration which was of 398 days (Apple) so that it can support all the browsers and new certificates worked without any issue.

Edit: 28-09-2020

Looks like all the Browser developers such as Google, Apple, Microsoft, and Mozilla have agreed to keep the SSL Certificate Lifespan common - 398 days. Please read more about it here:

Thanks!! Enjoy Programming!! :)

Saturday, 4 April 2020

Odoo: Qweb Templates Cache Issue

Hi Everyone, Today I was working on a hotel booking template in Odoo and changes made in the Qweb template(.xml) were not reflecting on updating module with odoo service restart. Tried few times without any success :(. Finally, I decided to delete the old template from Odoo backend and then update module again and it worked like a charm!! :)

Steps to delete template from backend:

Settings --> User Interface --> Views --> Search by template name

Delete the used template.

Although it's a small post, but I'm sure it will meet the purpose and help someone in the future.


Enjoy Programming!! :)

Reference Links:

Sunday, 29 March 2020

RHEL/CentOS 8 docker-ce installation Error: package docker-ce-3:19.03.8-3.el7.x86_64 requires >= 1.2.2-3

If you are facing the error while installing docker-ce as follow:

To fix it, you can either install a specific stable version like:

$ sudo dnf install docker-ce-3:18.09.1-3.el7


you can force the installation of docker-ce with the --nobest option

$ sudo dnf install --nobest docker-ce


Install the latest available package manually

$ sudo dnf install

After the package is installed, we can simply install the latest docker-ce

$ sudo dnf install docker-ce

This option is less convenient since the package is not installed 
as a dependency of docker-ce, therefore it will not be removed automatically when 
the latter is uninstalled from the system.

I hope it will fix your issue!!

Thanks!!!!!!! Enjoy Programming :)

Reference Links

Saturday, 28 March 2020

RHEL/CentOS 8 Error: problem with installed package podman-docker

If you guys are facing an error while installing Docker CE on Centos/RHEL 8 as follow:

Here is the workaround For CentOS/RHEL:

Uninstall podman before updating it sudo yum -y remove podman and install it back w/o manpages:
# install all podman dependencies except podman-manpages
sudo yum -y install oci-systemd-hook libvarlink
Then again install docker-ce

# install docker-ce
sudo yum -y install docker-ce
It should work this time!

If still facing an issue, try to use --nobest flag with command

$ sudo dnf -y  install docker-ce --nobest

Workaround for For Ubunutu:

sudo apt install -o Dpkg::Options::="--force-overwrite" podman

Thanks!!! Enjoy Programming :)

Reference Links:

Monday, 16 March 2020

RabbitMQ server issue - vhost ‘/’ is down

I'm using RabbitMQ with Celery(Django) for the last couple of months now but recently we faced an unexpected issue where RabbitMQ is not accepting tasks in its queues and error in logs say:

INTERNAL_ERROR — aess to prod_vhost ‘/’ refused for user ‘prod’: prod_vhost ‘/’ is down.`

Now, how to solve this problem:

From the Rabbitmq log file you can get the destination file URL, in my case it was

/var/lib/rabbitmq/mnesia/rabbit@hostname_1/msg_stores/prod_vhost/784WB90CIFDYO9LJI6DKMI78L/recovery.d ets”

If you have problem with vhost '/', most probably the file url will be

/var/lib/rabbitmq/mnesia/rabbit@hostname_1/msg_stores/vhosts/628WB79CIFDYO9LJI6DKMI09L/recovery.d ets”

Resolution :
  1. Stop 'rabbitmq-server'.
  2. delete the folder that contains the corrupt files. In this case: 784WB90CIFDYO9LJI6DKMI78L
  3. Start 'rabbitmq-server'. It should work fine now.

Thanks!!! Enjoy Programming!!!!!!! :)

Reference Link:

Monday, 27 January 2020

Odoo12/13: Add an extra action in the tree view action button

This post will help you to add an action window in Odoo.


<act_window id="action_make_bank_payment" 
            name="Do Bank Payment" 
            domain="[('type','=', 'in_invoice')]" 
            groups="account.group_account_user" />


<act_window id="action_make_bank_payment" 
            name="Do Bank Payment" 
            domain="[('type','=', 'in_invoice')]" 
            groups="account.group_account_user" />

Thanks!!! Enjoy Programming!! :)


Wednesday, 22 January 2020

What is 99.99% of Availability?

Service/Application Availability is defined by uptime. I.e. the time between failures. It is dependent upon

Downtime  - the amount of time the system is unavailable due to either failures or scheduled maintenance.

Recovery time - the average time it takes to recover from failures. 

Hence to have high availability, you must have low downtime and low recovery time.

What's 4 nines(99.99%) of availability? In simple math:

99.99% availability = (365*24*60) - (365*24*60*99.99/100) = 52.56 minutes = 52 minutes and 30 secs

Seven-nines or 99.99999%  - availability means 3 seconds or less of downtime in a year
Six-nines or 99.9999% - availability means 30 seconds or less of downtime in a year
Five-nines or 99.999% - availability means 5 minutes, 15 seconds, or less of downtime in a year
Four nines or 99.99% - availability allows 52 minutes, 33 seconds downtime per year
Three nines or 99.9% - availability allows 8 hours, 46 minutes downtime per year
Two nines or 99% - availability allows 3 days, 15 hours, and 40 minutes downtime per year.

Thanks!!! Enjoy Programming!!