A Passionate Techie

currently with docker you are limited to only linux machines and apps. It is like installing various zip files on your os. because of the use of base image we can save space.All the containers use the same base image. If you want 100 containers in traditional vm env you would have needed 100GB space considering 1gb per image but with docker you will need only 1gb of space. Suppose if you need emacs and apache then docker will add to separate images for it on top of each other and with the base image it will form a union image. this image is readonly so to write in it docker will place a writable container and the whole set container:image(apache)+image(emacs)+base image will make a whole container in the docker.  But the writable container is not persistent. Docker boots the image/ image layers on top f each other. apt-cache search docker.io ---will display a list of packages containing docker apt-chache show docker.io ---- will display all details of packaage Check...

Tutum is a platform to provide docker container as a service - cloud. Its equivalent docker universal control plane- on premise. n tutum you BYON and then tutum takes care of plumbing. Available in API,GUI,CLI. If there is any change in git repo code then tutum will automatically redeploy. in the node builder all the builds will occur if do not name a node as builder then all the build will occur on a node that has least amount of containers. All the repository build will happen inside tutum builder. Tutum has its own yaml file tutum.yml similar to docker-compose.yml. You can add a load balancer haproxy which is out-of-box which will automatically scale the application as per the requests. You can add the tags (tags are branches of git where you want to build) only the branches specified in the tag will be built for deployment. Tutum yaml is used when we create a stack in tutum. autoredploy: true

Setup Primary (Master) DNS Server Install bind9 packages on your server. Run the following command: "yum install bind bind-utils -y" 1. Configure DNS Server Edit  ‘/etc/named.conf’  file. vi /etc/named.conf Add the lines as shown in bold: // // named.conf // // Provided by Red Hat bind package to configure the ISC BIND named(8) DNS // server as a caching only nameserver (as a localhost DNS resolver only). // // See /usr/share/doc/bind*/sample/ for example named configuration files. // options {     listen-on port 53 { 127.0.0.1; [Master-dns ip] ; }; ### Master DNS IP ### #    listen-on-v6 port 53 { ::1; };     directory     "/var/named";     dump-file     "/var/named/data/cache_dump.db";     statistics-file "/var/named/data/named_stats.txt";     memstatistics-file "/var/named/data/named_mem_stats.txt";     allow-query ...

The Postfix configuration procedure is as below: The configuration files  main-cf  and  master-cf  are found in /etc/postfix folder. We can find where these files are located as shown below. Please find the master.cf and main.cf files, and make the configurations as are present in these files main-cf     master-cf By default, Postfix will forward mail from clients in authorized network blocks to any destination. Authorized networks are defined with the  mynetworks  configuration parameter. Many Virtual Machines can be relayed to an SMTP Server. For that the private IP's of these VMs need to be specified in the  mynetworks  configuration parameter in  main.cf  file.  In  main.cf  file edit the  mynetworks  parameter with the list of IPs of the VMs that uses the SMTP Server as a mailing Server. Specify the IP address of the machine  in CIDR (network/mask) notation or simpl...

Terraform is a tool for building, changing, and versioning infrastructure safely and efficiently. Terraform can manage existing and popular service providers as well as custom in-house solutions. Configuration files describe to Terraform the components needed to run a single application or your entire datacenter. Terraform generates an execution plan describing what it will do to reach the desired state, and then executes it to build the described infrastructure. As the configuration changes, Terraform is able to determine what changed and create incremental execution plans which can be applied. The infrastructure Terraform can manage includes low-level components such as compute instances, storage, and networking, as well as high-level components such as DNS entries, SaaS features, etc. The key features of Terraform are: Infrastructure as Code : Infrastructure is described using a high-level configuration syntax. This allows a blueprint of your datacenter to be versioned and...