Skip to main content

What Is Kubernetes.....

What Is Kubernetes.....

Running a container on a laptop is relatively simple. But, connecting containers across multiple hosts, scaling them, deploying applications without downtime, and service discovery among several aspects, can be difficult. 

Kubernetes is the one which addresses those challenges from the start with a set of primitives and a powerful open and extensible API. The ability to add new objects and controllers allows easy customization for various production needs. 

According to the website, Kubernetes is: 
"an open-source system for automating deployment, scaling, and management of containerized applications".

 Kubernetes is that it builds on 15 years of experience at Google in a project called borg.  Kubernetes is inspired by Borg - the internal system used by Google to manage its applications (e.g. Gmail, Apps, GCE).

Methodology of Kubernetes
Deploying containers and using Kubernetes may require a change in the development and the system administration approach to deploying applications. In a traditional environment, an application (such as a web server) would be a monolithic application placed on a dedicated server. 

As the web traffic increases, the application would be tuned, and perhaps moved to bigger and bigger hardware. After a couple of years, a lot of customization may have been done in order to meet the current web traffic needs. 

Instead of using a large server, Kubernetes approaches the same issue by deploying a large number of small web servers, or microservices. The server and client sides of the application expect that there are many possible agents available to respond to a request. 

It is also important that clients expect the server processes to die and be replaced, leading to a transient server deployment. Instead of a large Apache web server with many httpd daemons responding to page requests, there would be many nginx servers, each responding. 

Communication to, as well as internally, between components is API call-driven, which allows for flexibility. Configuration information is stored in a JSON format, but is most often written in YAML. Kubernetes agents convert the YAML to JSON prior to persistence to the database. 



Popular posts from this blog

Changing the FQDN of the vCenter appliance (VCSA)

This article states how to change the system name or the FQDN of the vCenter appliance 6.x You may not find any way to change the FQDN from the vCenter GUI either from VAMI page of from webclient as the option to change the hostname always be greyed out. Now the option left is from the command line of VCSA appliance. Below steps will make it possible to change the FQDN of the VCSA from the command line. Access the VCSA from console or from Putty session. Login with root permission Use above command in the command prompt of VCSA : /opt/vmware/share/vami/vami_config_net Opt for option 3 (Hostname) Change the hostname to new name Reboot the VCSA appliance.   After reboot you will be successfully manage to change the FQDN of the VCSA . Note: Above step is unsupported by VMware and may impact your SSL certificate and face problem while logging to vSphere Web Client. If you are using self-signed certificate, you can regenerate the certificate with the

Issue : Configure Management Network option is Grayed out into ESXi

Last week I got into an issue of one of my client into Vsphere environment where one of its ESXi went done out of the network. Issue was IP address was showing on main Esxi screen and when I tried to change the network configuration, its " Configure Management network option was greyed out.  I tried to gid into it and try to analyis its vmKernal and vmwarning logs. What I found is its VMkernal switch got removed due to unexpected reason. So to resolve the issue I tried to reconfigure its vswitch0 (vmk0) by going into Tech Mode of that Exi. Below are the steps which I followed to resolve the issue. 1) Login to ESXi 2) Press F2, Check if you " Configure Management network " is greyed out or not" if yes,    follow below 3) Press ALT+F1 to move the ESXi screen to tech mode   ( This is command line like dos) 4) login with root account 5) Run the following command into it esxcli network ip interface add --interface-name= vmk0

Collecting Logs from NSX-T Edge nodes using CLI

  This article explains how to extract the logs from NSX-T Edge nodes from CLI. Let's view the steps involved: 1) Login to NSX-T  Edge node using CLI from admin credentials. 2) Use of  " get support-bundle " for Log extraction. get support-bundle command will extract the complete logs from NSX-T manager/Edge nodes. nsx-manager-1> get support-bundle file support-bundle.tgz 3) Last step is to us e of " copy file support-bundle.tgz url " command. copy file will forward your collected logs from the NSX-T manager to the destination(URL) host from where you can download the logs. copy file support.bundle.tgz url scp://root@ Here, the URL specified is the ESXi host ( under /tmp partition where logs will be copied and from there one can extract it for further log review. Happy Learning.  :)