System Admin Q & A – XIX

Ques 1: – What is rbash & where it is used ?

Ans: – rbash is a restricted bash ,If bash is started with the name rbash, or the -r option is supplied at invocation, the shell becomes restricted. A restricted shell is used to set up an
environment more controlled than the standard shell. It behaves identically to bash with the exception that the following are disallowed or not performed:

changing directories with cd
setting or unsetting the values of SHELL, PATH, ENV, or BASH_ENV
specifying command names containing /
specifying a file name containing a / as an argument to the . builtin command
specifying a filename containing a slash as an argument to the -p option to the hash builtin command
importing function definitions from the shell environment at startup
parsing the value of SHELLOPTS from the shell environment at startup
redirecting output using the >, >|, <>, >&, &>, and >> redirection operators
using the exec builtin command to replace the shell with another command
turning off restricted mode with set +r or set +o restricted.

Ques 2: – How to recover deleted LVM partitions in Linux ?

Ans: – : Using the command “vgcfgrestore” we can recover deleted LVM partitions. Linux keeps the backup copies of lvm configuration in the /etc/lvm/archive directory

Ques 3: – What is Network bonding & why it is used ?

Ans: – Network Bonding / NIC Teaming is creation of a single bonded interface by combining 2 or more Ethernet interfaces. This helps in high availability and performance improvement.

Ques 4: – What is the chattr Command in Linux ?

Ans: – chattr is a command in the Linux operating system that allows a user to set certain attributes on a file residing on an ext2/ext3/ext4 based filesystem.

Syntax :

#chattr [operator] [switch] [file name]

Operator :
+ Add attribute.
– Remove attribute.
= Assign attributes (removing unspecified attributes)

Ques 5: – What is Grub bootloader in UNIX ?

Ans: – GRUB (GRand Unified Bootloader) is a boot loader package from the GNU Project. GRUB provides a user the choice to boot one of multiple operating systems installed on a computer or select a specific kernel configuration available on a particular operating system’s partitions.

Ques 6: – What is Tomcat?

Ans: – Tomcat is a Java Servlet container and web server from Jakartha project of Apache software foundation. A web server sends web pages as response to the requests sent by the browser client. In addition to the static web pages, dynamic web pages are also sent to the web browsers by the web server. Tomcat is sophisticated in this respect, as it provides both Servlet and JSP technologies. Tomcat provides a good choice as a web server for many web applications and also a free Servlet and JSP engine. Tomcat can be used standalone as well as behind other web servers such as Apache httpd.

Ques 7: – How do I configure Tomcat to work with IIS and NTLM?

Ans: – Follow the standard instructions for when the isapi_redirector.dll

Configure IIS to use “integrated windows security” In server.xml, make sure you disable tomcat authentication:

Ques 8: – Explain the concepts of Tomcat Servlet Container.

Ans: – Tomcat Servlet Container is a servlet container. The servlets runs in servlet container. The implementation of Java Servlet and the Java Server Pages is performed by this container. It Provides HTTP web server environment in order to run Java code and reduces garbage collection & native Windows and Unix wrappers for platform integration.

Ques 9: – What is Jasper?

Ans: – 1) Jasper is Tomcat’s JSP Engine. Tomcat 5.x uses Jasper 2, which is an implementation of the Sun Microsystems’s JavaServer Pages 2.0 specification.
2) Jasper parses JSP files to compile them into Java code as servlets (that can be handled by Catalina).
3) At runtime, Jasper is able to automatically detect JSP file changes and recompile them.

Ques 10: – Explain the concepts of Tomcat Servlet Container

Ans: – 1) A servlet container is a specialized web server that supports servlet execution.
2) It combines the basic functionality of a web server with certain Java/servlet specific optimizations and extensions (such as an integrated Java runtime environment, and the ability to automatically translate specific URLs into servlet requests).
3) Individual servlets are registered with a servlet container, providing the container with information such as the functionality, the URL used for identification.
4) The servlet container then initializes the servlet as necessary and delivers requests to the servlet as they arrive.
5) Many containers can dynamically add and remove servlets from the system, allowing new servlets to quickly be deployed or removed without affecting other servlets running from the same container.
6) Servlet containers are also referred to as web containers or web engines.

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