ServiceNow Interview Questions And Answers

1. Explain the benefits of using OpenStack Cloud?
Answer: Openstack is useful in developing any software-as-a-service (SAAS) applications, for new developments or to improve existing solutions.

It can serve as a strong foundation to deliver self-service storage to IT users.
It can deliver on-demand objective or block storage with higher scalability and easy-to-handle storage at lower costs.
Most enterprises can save bigger on licensing fees by switching virtual machines running on VMware to OpenStack.
Learn OpenStack in 16 hrs from experts

2. What is the meaning of Cell?
Answer: For scaling the compute cloud of OpenStack, Cell is used. It functions in a very simple way. The host gets divided into various groups and these are called cells.

3. What is Hypervisor?
Answer: VMM which is the abbreviation of a virtual machine monitor is defined by the Hypervisor. It is also used to define various components like firmware, hardware, and software. All these are part of the virtual machine. A hypervisor is mainly consisted of or included by the host machine or various other virtually available machines. Multiple Hypervisor is also available in the OpenStack developmental software program and can choose accordingly catering to specific uses.

4. How do Swift functions?
Answer: Swift helps in storing various objects. It helps in storing objects which are bigger and is also numerous in numbers. It helps in reducing data by storing such objects. Its works are often associated with a large number of sets of data. It contains data which are needed for virtual machines and other apps. Swift also has the capability of media streaming and can also secure a large number of objects stored by it. It has extreme scalability skills and can also help in backing up files and data.

5. Explain the Modular Architecture Of Openstack?
Answer: The three components that make modular architecture for OpenStack are:

OpenStack Compute: For managing large networks of the virtual machine.
Image Service: The delivery service provides discovery and registration for virtual disk images.
OpenStack Object Storage: A storage system that provides support for both block storage and object storage. 

6. What Is Bare-metal Node And What Does It Comprised Of?
Answer: It gives access to control bare metal driver, through which a user can control physical hardware resources on the same network.

Bare metal node is comprised of two separate components

Bare metal node Operating System: It is a base software, which runs on each node in the cluster.

Bare metal node Orchestrator: It’s management software, which acts as a dispatcher to all nodes in the cluster.

7. What Are Components Of Openstack Compute?
Answer: Nova Cloud Fabric is composed of the following major components:

API Server (nova-API)

Message Queue (rabbit-mq server)

Compute Workers (nova-compute)

Network Controller (nova-network)

Volume Worker (nova-volume)

Scheduler (nova-scheduler)

8. What Are Data Privacy Concerns In Openstack, How Those Can Be Remediated?
Answer: Data residency: Concerns over who owns data in the cloud and whether the cloud operator can be ultimately trusted as a custodian of this data have been significant issues in the past.

Data disposal:– Best practices suggest that the operator sanitize cloud system media (digital and non-digital) before disposal, release out of organization control or release for reuse.

Data not securely erased:- This may be remediated with database and/or system configuration for auto vacuuming and periodic free-space wiping.

Instance memory scrubbing, Cinder volume data, Image service delay delete feature.

9. What You Will Do In Case Of Server Failure?
Answer: 
If a server is having hardware issues, it is a good idea to make sure the Object Storage services are not running. This will allow Object Storage to work around the failure while you troubleshoot.

If the server just needs a reboot or a small amount of work that should only last a couple of hours, then it is probably best to let Object Storage work around the failure and get the machine fixed and back online. When the machine comes back online, replication will make sure that anything missing during the downtime will get updated.

If you cannot replace the drive immediately, then it is best to leave it unmounted, and remove the drive from the ring. This will allow all the replicas that were on that drive to be replicated elsewhere until the drive is replaced. Once the drive is replaced, it can be re-added to the ring.

10. What Does It Mean For The Cloud Ecosystem?
Answer: Wide adoption of an open-source, open-standards cloud should be huge for everyone. It means customers won’t have to fear lock-in and technology companies can participate in a growing market that spans cloud providers. Companies are already using OpenStack to provide public clouds, support, training and system integration services, and hardware and software products.

A great analogy comes from the early days of the Internet: the transition away from fractured, proprietary flavors of UNIX toward open-source Linux. An open cloud stands to provide the same benefits for large-scale cloud computing that the Linux standard provided inside the server.

11. What are the modular architectural components of OpenStack?
Answer: Following is a list of OpenStack modular architectural components:

  • Dashboard
  • Compute
  • Networking
  • Object Storage
  • Block Storage
  • Identity service
  • Image Service
  • Telemetry
  • Orchestration
  • Database Service
  • etc.

12. What are the different networking options used in OpenStack?
Answer: The networking options used in Open Stack are:

Flat DHCP Network Manager: It is used to fetch IP addresses from the subnet for VM instances but IP addresses to VM are assigned via DHCP (Dynamic Host Configuration Protocol).
Flat Network Manager: It is used to fetch IP addresses from the subnet for VM instances, and then injected into the image on launch.
VLAN Network Manager: VLAN provides a more secure and separate network to VMs. It has a physical switch to offer separate virtual networks and separate IP range and bridge for each tenant. It is a more preferable choice.

13. What is OpenStack and explain its uses?
Answer: The OpenStack is the most popular open source cloud computing platform that provides virtual machine resources and IaaS (Infrastructure as a Service) services to most of the customers. It captures the market in the future of cloud computing. All the services provided by the OpenStack can be accessed and managed through the GUI based user interface. The several benefits of the OpenStack Cloud Computing are mentioned below –

OpenStack boosts the business by eliminating maintenance services.
It improves agility and high availability.
Improves Efficiency and provides cloud infrastructure.
It provides great services for on-demand infrastructure services within no time.
OpenStack gives the opportunity of building own data center in turn which provides more control over the data being managed and controlled.
OpenStack enables rapid development.
OpenStack boosts high scalability and effective resource utilization.

14. What is Hypervisor and what are the different types of Hypervisors supported by the OpenStack Cloud?
Answer: The Hypervisor is defined as firmware or computer hardware used to provide virtual machine instances for the cloud computing instances and has different types of Hypervisors such as KVM, VMware, Containers, Xen, and Hyper-V which are explained as below –

KVM – This hypervisor is a virtualization layer in the Kernel-based Virtual Machine (KVM).
VMWare – This hypervisor is of type ESXi Hypervisor and enterprise-class version hypervisor.
Containers – This hypervisor is of cloud-native type hypervisor
Xen– This hypervisor is of type microkernel designed that provides services that allow multiple computer operating systems to execute the processes on the same computer hardware in concurrent mode.
Hyper-V – This hypervisor is also called Windows Server Virtualization used to create virtualized machines on Windows OS x86 – 64 version.

15. What is OpenFlow rule in OpenStack Cloud Networking?
Answer: This is the most asked Openstack Interview Questions in an interview. OpenFlow rule is defined as the reaching path of the data packet from source to destination in cloud computing. 

16. What Will You Do In Case Of Server Failure?
Answer: If a server is having hardware issues, it is a smart thought to ensure the Object Storage services are not running. This will permit Object Storage to work around the disappointment while you investigate.
If the server simply needs a reboot or a little measure of work that should just last two or three hours, at that point, it is most likely best to let Object Storage work around the disappointment and recover the machine settled and on the web. At the point, when the machine returns online, replication will ensure that anything absent amid the downtime will get refreshed.

If you can’t supplant the drive instantly, at that point, it is best to abandon it unmounted and expel the drive from the ring. This will permit every one of the limitations that were on that drive to be reproduced somewhere else until the point when the drive is supplanted. Once the drive is supplanted, it can be re-added to the ring.

17. What do you mean by OpenStack?
Answer: Most multinational firms characterize OpenStack as the bright future of Cloud Computing. The Internet and extensive volumes of data together have incited the reason for cloud computing, and OpenStack is one such platform to make and handle the vast group of virtual machines through the Graphical User Interface. It is an arrangement of proficient software tools to oversee private and open distributed computing stages.
OpenStack is free, open-source software and works like Linux.

18. What are the essential components of OpenStack?
Answer: Horizon: the main GUI in OpenStack; the primary part administrators see and get a thought of the present tasks in the cloud.
Nova: head figuring engine to deal with various virtual machines and computing tasks.
Swift: robust and reliable storage framework for objects and files helping engineers to allude to an extraordinary identifier and OpenStack chooses where to store the information.
Cinder: like a common PC storage system, it is a block storage framework in OpenStack for getting files speedier speed.
Neutron: guarantees proficient availability between parts amid deployment.
Keystone: a focal character list of all OpenStack cloud clients and gives different mapping systems to get to strategies against Keystone.
Glance: picture specialist provider where pictures are the virtual copies of the hard disks. Permits utilizing the images as layouts amid sending of new occasions.
Ceilometer: part giving billings services and other telemetry facilities to cloud clients. Keeps up a record of the part framework used by every client.
Heat (Orchestration Engine): Allows designers to organize/show and store the cloud application prerequisites and assets required in the file, in this manner keeping up the cloud framework.

19. What is OpenStack Python SDK?
Answer: Python SDK (Software Development Kit) helps users to write applications for performing automation tasks in Python by calling Python objects. It provides a platform to work with multiple OpenStack services in one place. It consists of language bindings to access OpenStack clouds, complete API reference, easy interaction with REST API and sample code for initial applications.

20. What is the meaning of the word Token in OpenStack?
Answer: Token is referred to as the validation required for any kind of authentication. The generation of Token mainly occurs after the insertion of the various credentials which are done by the users. Any type of services provided by OpenStack can be accessed by Token. However, the token can be used for a specified period and after that, it has to be renewed. The credentials of the users must be authentic to create a token.

21. What is Nova Scheduler?
Answer: Nova scheduler dispatches the request for new virtual machines to the correct to compute nodes based on configured weights and filters. Basically, it checks the different compute nodes based on some algorithms which helps it to create a virtual machine on which compute node.

22. Define the bare-metal node. What are its components?
Answer: The hardware resources can be controlled by users with the help of bare metal nodes which gives the users the right to control the bare metal driver. Its components are –

1. Bare metal node operating system – The is considered to be the software base for various nodes present in the cluster.
2. Bare metal node orchestrator – All the nodes when dispatched in the cluster is managed by this software.

23. What work does the Filter Scheduler do?
Answer: 
 If there is an instance of creating some new functions, the notification is mainly given by the Filter Scheduler. It also helps in filtering these notifications according to their importance. Compute Nodes are the ones with whom it works. The hosts which are unfiltered get created at first and by the help of their specific properties, it gets filtered. Such filtered hosts are needed according to the total number of instances.

24. What are the various functions of the command ‘nova’?
Answer: The functions of nova are as follows –

1. Compute resources are well managed
2. Authorization and networking
3. API based on the REST
4. Communication which is asynchronous
5. Supports Xen several and is hence considered to be Hypervisor agnostic
6. Helps in the management of instances

25. How can you overcome any type of sudden server failure?
Answer: During the failure of the server or when the server is not seen to be perfectly functioning then the Object Storage services should not be running. Hence, it is best to close them to this problem arises. This is because to know the solution, troubleshooting must be done. Closing the object storage service will allow it to work or function while troubleshooting is still going on. However, often such failure just needs rebooting and hence for this work which doesn’t require much time, the object storage service doesn’t need to be closed. Update to this service will be added once the machine gets online after rebooting. Removing the drive from the ring is the best idea when the driver can’t be replaced. But if it can be replaced, then it can be added back to the ring.

26. What Types Of Storage Openstack Compute Provides?
Answer: OpenStack provides two classes of block storage:

Volume Storage: It is persistent and not dependent on any particular instance. Volumes are created by users and within Quota
Ephemeral Storage: It is associated with a single instance. They effectively disappear when a virtual machine is terminated.

27. What are the two types of storage does OpenStack Compute provides?
Answer: OpenStack provides two classes of block storage,

Ephemeral Storage: It is associated with a single unique instance. Based on the instance, the size is defined. When the instance associated with it is terminated, data on ephemeral storage ceases to exist

Volume Storage: This storage is not dependent on any particular instance and is persistent. Volumes are user-created and within Quota.

28. Explain about OpenStack Python SDK?
Answer: For writing python scripts and managing in Openstack cloud, SDK (Software Development Kit) is used. The SDK implements Python binding to the OpenStack API, which enables you to achieve automation tasks in Python by making calls on Python objects instead of making REST calls directly.

29. Explain What Is Token In Openstack?
Answer: Token is an alpha-numeric string that allows access to a certain set of services depending upon the access level of the user.

30. What Is The Meaning Of Term “flavor” In OpenStack?
Answer: A flavor is an available hardware configuration for a server, which defines the size of a virtual server that can be launched.

31. What Are Functions And Features Of Swift?
Answer:

  • Storage of large-sized objects
  • Storage of a large number of objects
  • Data Redundancy
  • Archival capabilities – Work with large datasets
  • Data container for virtual machines and cloud apps
  • Media Streaming capabilities
  • Secure storage of objects
  • Extreme scalability
  • Backup and archival.

32. Why Compliance Is Required In Openstack?
Answer: Compliance means adhering to regulations, specifications, standards, and laws.

An OpenStack deployment may require compliance activities for many purposes, such as regulatory and legal requirements, customer needs, privacy considerations, and security best practices. The Compliance function is important for the business and its customers. 

33. What Is Sanitization Process?
Answer: The sanitization process removes information from the media such that the information cannot be retrieved or reconstructed. Sanitization techniques, including clearing, purging, cryptographic erase, and destruction, prevent the disclosure of information to unauthorized individuals when such media is reused or released for disposal.

34. What Is Alarm In Openstack?
Answer: Alarms provide user-oriented Monitoring-as-a-Service for resources running on OpenStack. This type of monitoring ensures you can automatically scale in or out a group of instances through the Orchestration module, but you can also use alarms for general-purpose awareness of your cloud resources’ health.

35. What Is Orchestration?
Answer: Orchestration is an orchestration engine that provides the possibility to launch multiple composite cloud applications based on templates in the form of text files that can be treated like code.

36. Mention What Are The Three Components That Make Modular Architecture Of Openstack?
Answer: The three components that make modular architecture for OpenStack are:

OpenStack Compute: For managing large networks of the virtual machine
OpenStack Object Storage: A storage system that provides support for both block storage and object storage
Image Service: The delivery service provides discovery and registration for virtual disk images.

37. What is CPU Pinning in OpenStack Cloud Computing?
Answer: The CPU Pinning is defined as the process of reserving the physical core parts of virtual machines specified as per the requirement. It is also called the process of isolating the CPU.

38. What are the secluded design segments of OpenStack?
Answer: OpenStack is an open source and free arrangement of programming instruments or distributed computing stage which is used for overseeing and building distributed computing stage for the private and open cloud.

39. Specify what are the three parts that make the OpenStack modular architecture?
Answer: The three parts that make modular architecture for OpenStack are:
OpenStack Compute: For overseeing extensive systems of the virtual machine.
OpenStack Object Storage: The storage framework that offers help for both object storage and block storage.
Image Service: The conveyance service gives disclosure and enlistment to virtual disk pictures. 

40. What is Token?
Answer: Token is a type of authentication similar to password-based validation. A token gets generated once the user inserts the credentials and authenticates as a Keystone user. The token can then be used to access OpenStack services without any revalidation. It is interesting to note that a token is active for a limited period and must be renewed after regular intervals.
To create a token, users first need to authenticate their Keystone credentials.

41. What are the components of OpenStack?
Answer: The following is the list of the components of OpenStack –

1. Horizon – This is the basic component of OpenStack and is also the most important operator
2. Swift – Files, and objects are mainly stored here and certain information also gets stored.
3. Nova – Various kinds of computing tasks are handled by this engine called Nova.
4. Cinder – This refers to a specific kind of block storage system and files can be accessed at a very fast rate with the help of this.
5. Keystone – All the identities of the various users of OpenStack is known to be the Keystone.
6. Neutron – It connects the various deployment components.
7. Glance – The hard disk consists of various copies virtually and these are provided by Glance.
8. Heat – This is known to be an illustrating engine which stores various cloud applications in files and hence the infrastructure is well maintained.
9. Ceilometer – The users are provided billing services by this.

42. What Are The Main Components Of Identity User Management?
Answer: Users: It is a digital representation of a person, service or system who uses OpenStack cloud services

Roles: A role includes a set of rights and privileges. A role determines what operations a user is permitted to perform in a given tenant

Tenants: A container used to group or isolate resources or identity objects. Depending on service operator a tenant may map to a customer, account, organization or project.

43. Give An Example Where Logs Help In Openstack Security?
Answer: For instance, analyzing the access logs of Identity service or its replacement authentication system would alert us to failed logins, frequency, origin IP, whether the events are restricted to select accounts and other pertinent information. Log analysis supports detection.

44. What Are Data Privacy Concerns In OpenStack? How Can Those Be Remediated?
Answer: Data residency: Concerns over who possesses data in the cloud and whether the cloud administrator can be at last trusted as a caretaker of this data have been critical issues previously.
Data disposal: Best practices recommend that the administrator cleans cloud framework media (non-digital and digital) before to disposal, discharge out of organization or release for reuse.
Data not safely deleted: This might be remediated with the database as well as framework setup for auto vacuuming and intermittent free-space wiping.
Instance memory scouring, Cinder volume data, Image service delay delete feature.

45. Characterize bare-metal mode?
Answer: It grants access to control bare metal driver that handles the provisioning of OpenStack Compute physical equipment using the standard cloud APIs and devices like Heat. It is by and large utilized for single inhabitant clouds like high-performance figuring. For utilizing the exposed metal driver, a system interface must be made with the uncovered metal hub embedded into it. After a while, clients can dispatch an occasion from the node. Clients can likewise list and delete the bare metal nodes by expelling the related system instances. 

46. Explain Flavor. How to assign a task/inhabitant to a client?
Answer: Flavors are virtual equipment layouts exhibit in OpenStack, which characterize the memory sizes of hard disks, RAM, and so on. Flavors represent various parameters like ID, Name, Memory_MB, Disk, and others, giving a decision of Virtual Machine to the client simply like having a physical server. OpenStack dashboard likewise enables clients to alter a flavor by erasing the current one and making another with the comparable name and parameters.
By utilizing command, sudo nova-oversee client makes client name.

47. Define the bare-metal node?
Answer: Bare-metal node grants access to control bare-metal driver that handles the provisioning of OpenStack Compute physical hardware utilizing the standard cloud APIs and tools like Heat. It is generally used for single-tenant clouds like high-performance cluster computing. For using the bare-metal driver, a network interface must be created with the bare-metal node inserted into it. Afterward, users can launch an instance from the node. Users can also list and delete bare-metal nodes by removing the associated network instances.

48. Which configuration management tool is used by pack-stack utility?
Answer: Pack-stack utility uses the puppet as the configuration management tool for automating the OpenStack installation. In the background, the puppet pushes the configuration to the nodes based on the answer file configuration.

49. What is Swift?
Answer: Swift is the object-based storage that bypasses the file system structure. We can directly upload and download the different objects on swift storage. It is used, where the read is more and write, are less to objects. Swift is equivalent to Amazon S3.

50. What are the key components of OpenStack?
Answer: Horizon: the only GUI in OpenStack; the first component administrators see and get an idea of the current operations in the cloud.

Nova: chief computing engine to handle multiple virtual machines and computing tasks

Swift: reliable and robust storage system for files and objects helping developers to refer to a unique identifier and Openstack decide where to store the info.

Cinder: similar to the traditional computer storage system, it is a block storage system in OpenStack for accessing files at a faster speed.

Neutron: ensures efficient connectivity between components during deployment.

Keystone: a central identity list of all OpenStack cloud users and provides various mapping techniques to access methods against Keystone.

Glance: image service provider where images are the virtual copies of hard disks. Allows using the images as templates during deployment of new instances.

Ceilometer: component providing billings services and other telemetry services to cloud users. Maintains an account of component system usage by each user.

Heat (Orchestration Engine): Allows developers to orchestrate/illustrate and store the cloud application requirements and resources needed in a file, thereby maintaining the cloud infrastructure.

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