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Showing posts with the label Centos

Managing & Configuring YUM [Centos 6.0]

Yum Configuration Hi Friends, we all have faced problems while configuring yum in RedHat, Fedora and Centos. Please find the below mention steps to use all the RPM packages come along with your distribution. Yum configuration will allow you to use them with proper dependency resolution. To configure yum you must have two packages, 1. yum 2. createrepo To obtain the same do the below mention just after you have mounted you disk. There could be two conditions a.) You have the distribution disk i.e. DVD. Please follow the below mention instructions to manage the same. Your system mush have the greater or equal space of DVD. # df -ah User the partition which has the space and create a directory. In my case /mnt has the space. # mount /dev/dvdwriter /mnt # cd /mnt/Packages/ # rpm -ivh yum-* --nodeps –force # rpm -ivh vsftps* -y # rpm -ivh createrepo* --nodeps --force # cp -rpvf /mnt/* /var/ftp/pub It will create the dump on /var/ftp/pub now we need to unmount the disk. # umount /mnt b.)...

Helm generic springboot templates

With the dramatically increasing demand for container orchestration specifically Kubernetes, demand to template K8S manifests(Json/Yaml) also came to light. To handle increasing manifests, new CRDs(Custom resource definition), etc… it became obvious that we need a package manager somewhat like yum, apt, etc… However, the nature of Kubernetes manifest is very different than what one used to have with Yum and Apt. These manifests required a lot of templates which is now supported by Helm, a tool written in GoLang with custom helm functions and pipelines. Neutral background on templating Templating has been a driver for configuration management for a long time. While it may seem trivial for users coming from Ansible, Chef, Puppet, Salt, etc…, it is not. Once one moves to Kubernetes, the very first realization is hard declarative approach that Kubernetes follows. It is difficult to make generic templating with declarative form since each application may have some unique feature and r...

Allowing users to have ssh access

Allowing users to have ssh access Hi Readers, It is one of the tasks we need to complete in order to allow users to log-in into your server without compromising your security. We are going to accomplish the following tasks, 1.) Allow the users for given domain only 2.) Must allow access to a given domain 3.) Block access for a specific domain. These questions are asked in RedHat certification examination RHCE6 We are going to complete the above mention task using iptables To give proper example we are taking 192.168.20.0/255.255.255.0 as our domain and 192.168.21.0/255.255.255.0 as other domain. Assuming that your system is a fresh installation we can remove all rules previously applied. # iptables -F The above mention command will flush all the previously applied rules. Insert a rule in your input chain by below mention command, # iptables -I INPUT -s <ip of your domain>/<subnet mask> -p <protocal tcp/udp> --dport <port> -...

Sent mail from perl

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 sub Mail_Mailer { my $destination_directory = '/data/' ; my $from_address = "abc@gmail.com" ; my $to_address = "abc@gmail.com" ; my $subject = "SOFT DATA " ; my $body = "Dear Sir\nPlease find the complete set of data on sftp\n." ; my $cc = "test@gmail.com" ; opendir (DES, $destination_directory ); my @files = readdir (DES); close (DES); my @mail_sent_file = @file ; foreach my $mail_file_names ( @mail_sent_file ) { $body = $ {body} . "\n" . $mail_file_names . "\n" ; } $body = $ {body} . "\nRegards\nreportsadmin." ; my $mailer = Mail:: Mailer -> new ( "sendmail" ) or die ; $mailer -> open ( { From => $from_address , To => $t...

Change password of mysql users

Change MySQL user's password in bulk Sometimes we need to change the password of mysql users at bulk. Lets say your company has fired a group of peoples or dissolved a project. This requirement can be supplied as : We can achieve the same by changing the password field in mysql.user table. Password() is a predifined method in mysql which generates encrypted value of a certain string. host update mysql.user set password = PASSWORD("passwd") where host IN (<Comma separated list of HostName/IP>); user update mysql.user set password = PASSWORD("passwd") where user IN (<Comma separated list of ‘user’@’host’>);

Istio multicluster, gotchas ....

istio.md Istio lets you connect, secure, control, and observe services. At a high level, Istio helps reduce the complexity of these deployments, and eases the strain on your development teams. It is a completely open source service mesh that layers transparently onto existing distributed applications. It is also a platform, including APIs that let it integrate into any logging platform, or telemetry or policy system. Istio’s diverse feature set lets you successfully, and efficiently, run a distributed microservice architecture, and provides a uniform way to secure, connect, and monitor microservices. In context of Vuclip istio allows us to reduce the code and environment configurations while keeping the similar or more feature sets at our disposal. Since istio is designed to bridge the gap for both development teams and SRE, it is essential to see and visualize that in practice. Istio will affect us in our ability to connect , secure(HTTPs TLS, mtls [Phase-2]), control(external comm...