Looking for Red Hat interview questions? Here are 10 questions frequently asked when it comes to applying for a Red Hat-based job.
Red Hat, Inc. is an American multinational software company providing open-source software products to the enterprise community. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina, with other offices worldwide. It became a subsidiary of IBM on July 9, 2019.
Red Hat has become associated to a large extent with its enterprise operating system Red Hat Enterprise Linux. With the acquisition of open-source enterprise middleware vendor JBoss, Red Hat also offers Red Hat Virtualization (RHV), an enterprise virtualization product.
Red Hat provides storage, operating system platforms, middleware, applications, management products, and support, training, and consulting services. Source: Wikipedia
1. What is a Puppet server?
Puppet is an enterprise application for configuration management toll in Unix-like operating systems. It is an open-source automated software used to push the configuration to puppet agents with the help of code. Installing new software, verifying file permissions, updating the user accounts, and other tasks can be easily done or performed with the help of Puppet code.
2. What is a storage cluster?
A question on the concept of storage cluster is one of the most frequently asked Red Hat interview questions. A Cluster is defined as two or more computers that are combined to perform tasks. Storage, high availability, load balancing, and high performance are the different types of clusters available.
The storage cluster is used to provide a consistent view of file systems in all the servers within a cluster. It helps servers to read and write simultaneously to a single shared file system. It also simplifies storage administration by limiting the installation and patching of applications to a single file system.
3. What is the difference between ulimit and umask?
Ulimit is a Linux built-in command that provides control over the available resources to the shell or started processes. A user can limit to a specific range by editing the limits.conf file, and the system settings can be updated in sysctl.conf file.
Umask refers to the user file creation mask. When a file or directory has been created, umask determines permissions for files and directories.
4. What do you mean by SELinux?
SELinux is known as Security-Enhanced Linux. It helps in protecting the server from misconfiguration and compromised daemons. It is used as a security feature and implements access control for the Linux kernel. SELinux is used to put limits and instruct the server programs to access specific or permission-granted files. It also defines the security policy for the actions that can be taken.
5. Explain cman and rgmanager in a Red Hat cluster.
Cman is the cluster manager. It runs in each cluster node. Cman helps in keeping track of cluster quorum by monitoring the cluster nodes. The manager is responsible for monitoring, voting, quorum, heartbeat, and communication between the cluster nodes.
Rgmanager is the resource group manager. It manages the collection of cluster resources i.e., services, resource trees, and resource groups. It helps red hat administrators to configure, define, and monitor cluster services. If a node failure occurs, rgmanager will try to handover the same clustered service again to another node with minimal service disruption.
6. What do you know about DAS?
It is a block device from a disk that is physically attached to the host machine. A filesystem should be there on the machine to use DAS. Only a defined number of servers can access this device. This storage device needs to be close to the server storage and dedicated resources.
Sometimes, it is not possible to dedicate the hard disk to multiple computers. DAS as a solution is easy to configure and is less expensive. It includes IDE, SCSI, and SATA technologies.
7. What is a Load Balancing cluster?
As the name suggests, a load balancing cluster is used to balance the request load. The cluster dispatches the network service requests to multiple cluster nodes. It provides cost-effective scalability as several nodes can be matched according to the load requirements.
In a load-balancing cluster, if a node is not working properly, it will check the failure and assign the requests to other cluster nodes that are available. In this type of cluster, node failures are not visible to clients outside the cluster. Load balancing add-on is an essential component of this kind of cluster.
8. What is an Inode and how does it work?
An inode is a data structure of the file system for Unix-like operating systems. It helps in storing all the information about the file without using its actual name and data on Linux and other Unix-like operating systems. An inode number is a unique number that is generated within the file system when a file is created. A name is also provided to the file.
The name and inode number are stored in directories as entries for the user who has access to the files. It helps the user in recovering the damaged file system. If an inode is lost, it will appear in the lost + found directory. Red Hat interview questions are incomplete without inode.
9. What are NAS and SAN?
NAS is a device that runs in an embedded operating system on simplified hardware like a monitor or keyboard. It is used to authenticate clients and also provides sharing options to other computers or users on a network that requires a dedicated IP address for accessing it.
Automatic or manual backups can be set with the help of software programs; these programs can also be used to copy files between NAS and other connected devices. Other facilities include setting user permissions, folder privileges, and restricting access to documents.
SAN is a block-level storage solution. It is an optimized solution for a high volume of block-level data transfer. It is highly scalable in terms of capacity and performance. It provides storage and simultaneous access to multiple files while streaming audio, video, cloud computing, etc. SAN is an architecture to attach remote storage which appears as it is locally attached.
10. What are suid and sgid?
Suid provides the same permissions that the owner of a file has to a user executing the same file.
Sgid inherits the group privileges of the execution file. It inherits the group ownership of directories when a file is created within the directory.
These are the 10 most frequently asked Red Hat interview questions. If you think there are other Red Hat interview questions essential to cracking the interview (administration, development, etc.), do comment. And if you have successfully cleared a Red Hat interview, we’d love to know about your experience.