profile for Gajendra D Ambi on Stack Exchange, a network of free, community-driven Q&A sites

Thursday, July 20, 2023

Windows bluetooth crackling sound [cause, solution]

 So I had/have this issue with windows where bluetooth speakers start producing cracklintg/cracking sound for no reason. scraping the internet yielded no solution. Windows troubleshooter has solved no problem in all these years and that stays the same today. Here are the details:

Type of PC: laptop

make: 2023

Ram: 32GB

GPU: Integrated RTX4080

OEM: Asus


Wireless I/O devices:

  1. keychron k2 wireless keyboard (bluetooth)
  2. logitech m720 mouse (bluetooth)
  3. logitech g pro mouse  (2.4ghz unifying logi dongle, not bluetooth)
  4. harmon kardon aura studio 3 (bluetooth)

What didnt work?

  1. windows inbuilt troubleshooter
  2. driver update
  3. driver reinstall
  4. reinstall OS
  5. Unpair all bluetooth devices, uninstall, pair them again, update their drivers (via windows udpate driver)
  6. External USB bluetooth 5.0 dongle
What worked?
  1. Except bluetooth speaker and bluetooth keyboard, dont use any more bluetooth devices
Theoretically bluetooth supports 6 to 7 bluetooth devices but in practice due to bandwidth throtting by OEMs & bandwidth limitation of the BT technology, if BT speakers are used, then use just 1 more BT device and not anymore.
So currently the 2 mice that I have from logitech, they both come with their proprietory dongle to connect with, it takes up 2 more USB ports on the laptop (So I bought a docking station) but at least it is headache free.
Suggestions to OEMs:
1. Make multi device bluetooth keyboards but which can be paired with mouse, so whenever I switch connection between devices, the mouse+keyboard switch together.
2. Make PC, Laptops support multiple bluetooth interfaces, just like multiple NIC/PCI/PCIe cards, and we can connect our devices to any of the BT interface in the OS.

Friday, May 26, 2023

Postgresql on cloud, self or hosted, if self then monolithic or k8s? which k8s operator?

 So I have been planning to move my django sites to kubernetes to get that automated horizontal and vertical scaling, failover, high availability, fault tolerance and other good stuff. Database on kubernetes has been a very huge topic of , to do or not to do...yes a year back, I would not have recommended it. Operators were just kicking in. Now many seem to have matured everyone has their own querks and problems.

Why not hosted?

There are many DBaaS. All cloud providers provide one. Many provide only DBaaS such as elephantSQL. What I am afraid about is freedom, loss of freedom. We all know what happened to, they got just booted off their cloud account, data gone, applications gone. One day their account just got locked out. So all these DBaaS providers do not offer replication, backup to intracloud target (that is, having a standby node on another competing cloud provider, or your own on prem server or an object storage from some other provider or a NAS server at home etc.,). Sure they provide headache free, automated, regular backup, PITR - point in time recovery, base backup, incremental backup, differential backup, standy node etc., You dont have to have a team of DB engineers who maintain it and do all these day 2 operations. You remember what happened to gitlab dont you? Engineer accidentally deleted their entire primary postgresql database. Yes, they did and they found out that the backups that they had were no good.  So you are outsourcing all your headache to someone else. This is good, but not enough.

I want to be able to have my backup or replication or DR solution on some other site, some other cloud provider or a target of my choice. 

Self hosted: Monolithic or k8s

If you go monolithic then I highly recomment citus. It is an extension, which allows you to scale, shard at will and it is a clustering solution so you get the HA. There are of course the OG solutions like perconi, patroni, EDB, many paid, free and opensource solutions. You do however have to learn all these implentations, do a POC in house, verify all DR options, test HA, FT before going for any of them.

Self hosted: k8s operator

I considered and evaluated






but went with cnpg aka cloud native postgresql operator. Why? because of the first 2 words. Cloud native. Everyone else is trying to adopt what has been tested in the monolithic world to kubernetes world to get that autoscaling, inbuild HA, FT, auto recovery options from k8s but they are built for cloud or k8s, they are adopted to cloud/k8s. cnpg is built for k8s. Also their documentation was a lot better than any of the top above,udpated and their example deployment manifests per different options, just work. 

So wish me luck. I hope all my django apps stay afloat and sail smoothly because their DB is sailing smoothly.

Tuesday, February 28, 2023

The Coma question!

 In any organization, employees play a crucial role in determining the success or failure of the company. As a result, it is essential for companies to identify the different types of employees and understand their behavior to create an efficient and effective work environment. In this blog post, we will discuss the three types of employees and how companies can handle them.
1. Company's interest
Prioritizes company's interest first. These employees are highly motivated and committed to the success of the company. They understand the importance of creating redundancy for themselves and cross-skilling others in the team. By automating most of their work, they reduce dependency and help the organization save resources. These employees focus on the bigger picture and prioritize the company's goals over their personal interests. They are reliable, proactive, and always look for ways to improve processes. This thereotically should benefit his upward movement since whatever that he is responbile for, has been brought to such s state and stage that it can be taken care of without him and thus he can move on or up to something else.

2. Manager's interest
Prioritizes manager's interest first. Here is manager does not necessarily mean manager or management, it is always the immediate person in heirarchy of reporting or decision making. Employees who work for their manager prioritize pleasing their superiors over the company's success. They tend to be complacent and avoid suggesting improvements or corrections, even if it negatively affects the company. These employees are not proactive, and they are not interested in acquiring new skills or knowledge. They tend to be average workers, and their performance is dependent on the management's approval. Such employees often lack the motivation to go beyond their job description, which results in mediocre output. Advantage here being, managers too are humans and thus yes men do the leg up every now and then.

3. Self interest
prioritizes self interest. Employees who work for themselves prioritize their personal goals over the company's success. They create dependency on themselves, which means that if they are not there, most of the things will be on halt or put on hold. These employees tend to be less collaborative, and they do not share knowledge or skills with other team members. They choose projects or tools that increase their dependency and keep the number of resources needed high.Now, let's discuss how companies can handle these three types of employees.For employees who work for the company, companies need to ensure that they are motivated and engaged. They need to be given opportunities to learn new skills and take on new challenges. Companies should also recognize and reward their efforts to create redundancy and reduce dependency. By doing so, companies can retain these employees and build a strong and committed workforce. As long as there is a dependency on him, he will be the gatekeeper and gets to decide who passes in or out of his domain, whether it is the domain or technology that he is working on or controls. This will not only ensure his job security but also any action by management. Management would often sacrifice type 1 and type 2 employees to satisfy this kind of employees else the business won't run or may stop.

For employees who work for their manager, companies need to encourage them to think beyond their job description. They need to be given opportunities to provide feedback and suggestions, which can help improve processes and ultimately benefit the company. Companies should also encourage these employees to acquire new skills and knowledge. This can help them become more proactive and engaged, which can benefit the company in the long run.
For employees who work for themselves, companies need to create a culture of collaboration and knowledge sharing. They need to encourage these employees to work with others and share their skills and knowledge. Companies should also identify areas where these employees can reduce dependency and create redundancy. By doing so, companies can reduce the risk of critical knowledge loss and ensure that operations continue even when these employees are not available.
When employees of type 1 feel ignored or taken for granted, they drop down to type 2 or 3.  It ultimately depends on how rewarded they are in regards to their efforts, contributions and how secure they feel about their job.
Imagine a business which charges for support for its products but their documentation is so good that you do not need support to set it up and their product is so good that it rarely crashes or has problems and if it is also opensource, people can just do a PR against their git repo for hotfix and bugfix, then they will greatness of the product will drive them out of business. Sure, there will always be bugs, new features to add etc., SUSE, Rehdat all operate on such model and they have not gone out of business. Microsoft products, apple products on the other hand are an example of the opposite business model. Their profit it directly proportional to minimal transparency (of code or product design), maximum dependency and any support you might need for fix, repair or upgrade. Businesses do the type 3 modeling against their customers all the time.
COMA Question!
So how do you know who is who? Simple!. Ask yourself this question. If X is in coma for a month, what will be the impact on the show? Low(Type 1 employee), Medium(Type 2 employee), High(Type 3 employee).  
Redundancy loop!
Your redundancy loop should try to be as big as the size of the team. A has created redundancy in B, B has created redundancy in A, that makes it the smalles loop which is wrong. It should be A's redundancy is B, B's redundancy is C, C's redundancy is A, if you have ABC members in your team. 
Employees play a crucial role in the success of any organization. By understanding the behavior of different types of employees, companies can create an efficient and effective work environment. Companies need to ensure that their employees are motivated, engaged, and focused on the company's success. By doing so, they can build a strong and committed workforce that can help them achieve their goals.

Tuesday, February 21, 2023

Hackerproof injection of secrets in kubernetes where none but your apps can use variables & secrets

 Okay, okay. It is not exactly hacker*proof* but definitely hacker resistant (you know like water resistant but not water proof). When we inject secrets into pods either via 

  1. mounting, 
  2. setting environment variables
  3. using a helm values file with secrets and env vars
  4. using CICD to inject while deployment
  5. most tidious way: read from vault but this requires a role_id, secret_id of vault to be against set in pod as environment variable or some other way. Circular problem.
We stumbled upon a problem which actually ended up as a solution for our longterm question. How to hide secrets from a hacker or a rogue app which does ssh to the pod. If I am a hacker, I have ssh access to the pod, then I can see all secrets and environment variables. Can i set them up where only app can see it and nobody can?
  1. open up 2 shells
  2. In shell 1 open your bashrc file, set some export or env vars and save.
  3. Do `. /path/to/bashrc fiile' (notice the dot and a space after it)
  4. In shell 1 you can access your new environment variable
  5. In shell you cant or wont
  1. open up 2 shells
  2. in shell one set an environment variable in the shell export xyz=abc and see if you can access it. you do.
  3. In shell 2 you cant access the same.
Solution based on the above.
  1. Mount secrets via vault or some place to some location in the pod /path/to/my/mount/vaultsecrets
  2. In your file for your app, somewhere before you start your app, add `. /path/to/my/mount/vaultsecrets
Now when your pod on first boot, runs the, it sources all vars from your mount point and then starts your app in the same tty shell which means only this shell can access these environment variables and not the entire OS.
I had this secret injection employed with helm yaml file and I was itching for a more secure option to ensure nobody sees the secrets even if they connect to the pod but when we migrated from gitlab to github and github actions, my associate opted in this sidecar injection along with the helm yaml we had. It seems this unintended parallele secret injection via sidecar came as a blessing.
gotcha: So a hacker can literally manually run the command in the point no.2 and get the secrets?! Yes. but you can also add add another step after point. 2. Unmount that path. So now, you mounted the secrets, sourced it to a particular tty shell of the app and then unmounted it. 

Sunday, February 12, 2023

VMs (Virtual Machines) on k8s with kube-virt against VMs on openstack or hypervisors

Virtual Machines (VMs) have been a popular way of deploying and running applications for many years. With the advent of cloud computing and the need for scalable, highly available infrastructure, VMs have found new homes in platforms like OpenStack and Hypervisors. But with the rise of Kubernetes, VMs on Kubernetes with KubeVirt have become increasingly popular, offering several advantages over traditional VMs on Hypervisors and OpenStack.

  1. Improved Resource Management: Kubernetes, with its powerful scheduler, ensures that VMs are efficiently deployed and resourced according to the requirements of the applications they host. This results in a more optimized and cost-effective deployment, as VMs are only given the resources they actually need, instead of being over-provisioned.

  2. Enhanced Networking: KubeVirt integrates with the Kubernetes networking model, providing a powerful and flexible way to manage network connections between VMs and other components within a cluster. This allows for easy scaling and migration of VMs without having to worry about network configurations.

  3. Improved Security: VMs on Kubernetes with KubeVirt can leverage Kubernetes security features, such as network segmentation, secrets management, and pod security policies, to provide a secure and controlled environment for deploying applications.

  4. Easier Migration: One of the biggest benefits of VMs on Kubernetes with KubeVirt is that they can be easily migrated between clusters and across cloud providers. This makes it easier for organizations to move their applications to new infrastructure as needed, without having to worry about compatibility issues or reconfiguring network connections.

  5. Increased Flexibility: KubeVirt provides a unified way to manage both VMs and containers within a single cluster, giving organizations greater flexibility in choosing the best deployment option for their applications. This allows for a more streamlined and efficient deployment process, as well as the ability to run legacy applications in a modern, scalable infrastructure.

In conclusion, VMs on Kubernetes with KubeVirt offer several key advantages over traditional VMs on Hypervisors and OpenStack, including improved resource management, enhanced networking, improved security, easier migration, and increased flexibility. As organizations look to modernize their infrastructure and move to the cloud, VMs on Kubernetes with KubeVirt are becoming an increasingly popular choice, offering a powerful and scalable platform for deploying applications.