Lectures Tehnotreka. Linux administration

We present to your attention the next batch of Technotrack lectures. The course will cover the basics of system administration of Internet services, ensuring their resiliency, performance and security, as well as features of the device OS Linux, the most widely used in such projects. As an example, the distributions of the RHEL 7 family (CentOS 7), nginx web server, MySQL DBMS, bacula backup systems, Zabbix monitoring systems, oVirt virtualization systems, ipvs + keepalived load balancer will be used. The course is taught by Sergey Klochkov, a system administrator at Variti.

List of lectures:

1. The basics .
2. Linux user environment .
3. Linux and network (basics) .
4. User environment management .
5. Web services .
6. Data storage
7. Infrastructure services .
8. Backup
9. Backup (part 2) .
10. Email infrastructure .
11. The distribution of system resources .

Lecture 1. Basics

At the beginning of the lecture you will learn about the history of the emergence and development of Linux. Then there is a tour of the Linux ecosystem, telling about some of the differences between distributions. Next, the hierarchy of the file system is discussed, and the main working tool in this OS is the command line. Details about the Bash scripts, about the two main entities in the system - users and groups. Then, the regulation of access rights to files and directories is discussed, the privileges of users are considered and, at the end of the lecture, the subject of remote access is touched upon.

Lecture 2. Linux user environment

First, it details the stages of booting the system and OS, discusses the Linux kernel. It explains what a "process" is, how it uses RAM. You will learn what descriptors are and what they are for, how the processor consumes resources. Then, system calls, signals, process limits, environment variables are considered. The issue of reproduction processes is discussed and the process operation is analyzed in detail. Finally, you will learn about the perf subsystem and logs.

Lecture 3. Linux and network (basics)

You will learn what a network stack is and an OSI model. Remember what Ethernet is and how Linux works with it. Your knowledge of using IPv4, features of IPv4-packages and networks will be further refreshed. Then ICMP, multicast to IPv4, is considered. Next, go to IPv6, IPv6 packet headers, UDP, TCP connections are discussed. The subject of TCP congestion control is affected. Then he talks about NAT, application-level protocols, DNS, NTP, HTTP, and URLs. HTTP response codes (successful responses and errors) are parsed.

Lecture 4. User environment management

You will learn what an RPM package manager is and how to use it. The following describes the classic init systemd system manager. Understands the example init file. Discusses the main types of Unit'ov, tells about the system logger and log rotation. Finally, you will learn about the basics of network interface configuration.

Lecture 5. Web services

First, a typical web service architecture is considered. It tells about what a frontend is, what an application server is. Understands the issue of data storage by web applications. Detailed understanding of the work and the use of the HTTP protocol. Discusses the types of HTTP requests. The topic of creating encrypted tunnels with SSL is touched. Then we consider examples of installing MySQL DBMS with the creation of a database and a user. It works with PHP-FPM, configuring nginx, installing and configuring a wiki engine.

Lecture 6. Data Storage

Lists the main problems of data storage, discusses the advantages and disadvantages of different storage devices, their interfaces. Then you will learn how to determine the status of the hard disk, what is its performance, what is RAID, what are the RAID-arrays and how to create them. Different types of RAID are compared, as well as software and hardware arrays. LVM snapshots are discussed, different file systems are considered. The issue of remote data storage and the use of iSCSI protocol is affected.

Lecture 7. Infrastructure services

We consider the bind DNS server, NTP server. Discusses LDAP-based central authentication. DHCP is dealt with, the task of installing an OS over the network with the help of kickstart, and finally, the configuration management system Salt is considered.

Lecture 8. Backup

The beginning of the lecture is devoted to the continuation of the story about the configuration management system Salt. Describes how to install it, how to manage the configuration of Linux, understands its example. You will learn what “grains” are and why they are needed. Next, go to the backup topic: what data you need to copy, what are the main difficulties, what are the types of backups. The task of backing up the OS is discussed. It tells about the use of bacula backup system.

Lecture 9. Backup (Part 2)

At the beginning of the lecture tells about the backup database. Various backup strategies are discussed - mysqldump, mylvmbackup. You will learn what monitoring is for and how to carry it out, what are the means of monitoring. Different types of checks are considered. Discussion templates are discussed. In conclusion, describes the elements of data on the implementation of web monitoring.

Lecture 10. Email Infrastructure

You will learn what e-mail is, get to know the basic concepts. Then the process of delivery and delivery of mail is considered. The use of SMTP, POP3, and IMAP protocols is discussed. Understands the use of postfix SMTP server, Dovecot IMAP server. Describes how email goes around and what MX records are. Finally, spam protection is discussed, SPF records, DKIM and Spamassassin are sorted out.

Lecture 11. Distribution of system resources

The lecture is dedicated to advanced Linux administration issues. First, you will learn how to manage the parameters of the OS kernel. Then, kernel modules are considered, how to manage them. Discusses the allocation of application resources. The following describes the task scheduler, the scheduling algorithms, and the process priorities. Understands CFS Sheduler, Sheduling Policies. You will learn what NUMA is and how to work with it. Get to know the I / O schedulers. The following describes control groups, managed resources, control group management, and I / O limits.

Playlist of all lectures is on the link . Recall that current lectures and master classes on programming from our IT specialists in Technopark, Technosphere and Tehnotrek projects are still published on Tekhnostrim channel.

Other courses Tehnotreka on Habré:

• Lectures Tehnotreka . Java Development (Spring 2016)
• Lectures Tehnotreka . Designing a DBMS (Fall 2016)
• Lectures Tehnotreka . Basics of web development (spring 2016)

Information on all our educational projects can be found in a recent article .