Showing posts with label widely. Show all posts
Showing posts with label widely. Show all posts

December 26, 2019

Top 20 Docker Interview Questions & Answers

Ques: 1. What do you understand by Docker?
Ans: Docker is an open-source lightweight containerization technology. It has gained widespread popularity in the cloud and application packaging world. It allows you to automate the deployment of applications in lightweight and portable containers.

Ques: 2. What is Docker image?

Ans: The Docker image help to create Docker containers. You can create the Docker image with the build command. Due to this, it creates a container that starts when it begins to run. Every docker images are stored in the Docker registry.

Ques: 3. What is Virtualization?

Ans: Virtualization is a method of logically dividing mainframes to allow multiple applications to run simultaneously.

However, this scenario changed when companies and open source communities were able to offer a method of handling privileged instructions. It allows multiple OS to run simultaneously on a single x86 based system.

Ques: 4. Can you explain the process of scaling your Docker containers?
Ans: The Docker containers can be scaled to any level starting from a few hundred to even thousands or millions of containers. The only condition for this is that the containers need the memory and the OS at all times, and there should not be a constraint when the Docker is getting scaled.

Ques: 5. What is CNM?

Ans: CNM stands for Container Networking Model. It is a standard or specification from Docker, Inc. that forms the basis of container networking in a Docker environment. This docker's approach provides container networking with support for multiple network drivers.

Ques: 6. Can you explain the Docker Trusted Registry?

Ans: Docker Trusted Registry is the enterprise-grade image storage toll for Docker. You should install it after your firewall so that you can securely manage the Docker images you use in your applications.

Ques: 7. How do I run multiple copies of Compose file on the same host?

Ans: Compose uses the project name which allows you to create unique identifiers for all of a project's containers and other resources. To run multiple copies of a project, set a custom project name using the -a command-line option or using COMPOSE_PROJECT_NAME environment variable.

Ques: 8. What is Hypervisor?

Ans: A hypervisor is a software that makes virtualization possible. It is also called Virtual Machine Monitor. It divides the host system and allocates the resources to each divided virtual environment. You can basically have multiple OS on a single host system. There are two types of Hypervisors:

Type 1: It’s also called Native Hypervisor or Bare metal Hypervisor. It runs directly on the underlying host system. It has direct access to your host’s system hardware and hence does not require a base server operating system.

Type 2: This kind of hypervisor makes use of the underlying host operating system. It’s also called Hosted Hypervisor.

Ques: 9. What is containerization?

Ans:In the software development process, code developed on one machine might not work perfectly fine on any other machine because of the dependencies. This problem was solved by the containerization concept. 

So basically, an application that is being developed and deployed is bundled and wrapped together with all its configuration files and dependencies. This bundle is called a container. Now when you wish to run the application on another system, the container is deployed which will give a bug-free environment as all the dependencies and libraries are wrapped together. Most famous containerization environments are Docker and Kubernetes.

Ques: 10. What is the difference between virtualization and containerization?

Ans: Once you’ve explained containerization and virtualization, the next expected question would be differences. The question could either be differences between virtualization and containerization or differences between virtual machines and containers. Either way, this is how you respond.

Containers provide an isolated environment for running the application. The entire user space is explicitly dedicated to the application. Any changes made inside the container is never reflected on the host or even other containers running on the same host. Containers are an abstraction of the application layer. Each container is a different application.

Whereas in Virtualization, hypervisors provide an entire virtual machine to the guest(including Kernal). Virtual machines are an abstraction of the hardware layer. Each VM is a physical machine.

Ques: 11. Explain Docker Architecture?

Ans: Docker Architecture consists of a Docker Engine which is a client-server application with three major components:

  1. A server which is a type of long-running program called a daemon process (the docker command). 
  2. A REST API which specifies interfaces that programs can use to talk to the daemon and instruct it what to do. 
  3. A command line interface (CLI) client (the docker command). 
  4. The CLI uses the Docker REST API to control or interact with the Docker daemon through scripting or direct CLI commands. Many other Docker applications use the underlying API and CLI.

Ques: 12. What is a Dockerfile?

Ans: Let’s start by giving a small explanation of Dockerfile and proceed by giving examples and commands to support your arguments.

Docker can build images automatically by reading the instructions from a file called Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build, users can create an automated build that executes several command-line instructions in succession.

Ques: 13. What is the life cycle of a Docker Container?
Ans: This is one of the most popular questions asked in Docker interviews. Docker containers have the following life cycle:

  • Create a container 
  • Run the container 
  • Pause the container(optional) 
  • Un-pause the container(optional) 
  • Start the container 
  • Stop the container 
  • Restart the container 
  • Kill the container 
  • Destroy the container

Ques: 14. How do you scale your Docker containers?
Ans: Docker containers can be scaled to any level, starting from a few hundreds to even thousands or millions of containers. The only condition is that the containers need the memory and the OS all the time, and there should not be a constraint on these when the Docker is getting scaled.

Ques: 15. What is the difference between the COPY and ADD commands in a Dockerfile?

Ans: Although ADD and COPY are functionally similar, generally speaking, COPY is preferred. 

That’s because it’s more transparent than ADD. COPY only supports the basic copying of local files into the container, while ADD has some features (like local-only tar extraction and remote URL support) that are not immediately obvious. Consequently, the best use for ADD is local tar file auto-extraction into the image, as in ADD rootfs.tar.xz /.

Ques: 16. What are the most common instructions in Dockerfile?

Ans: Some of the common instructions in Dockerfile are as follows:

  • FROM: We use FROM to set the base image for subsequent instructions. In every valid Dockerfile, FROM is the first instruction. 
  • LABEL: We use LABEL to organize our images as per project, module, licensing etc. We can also use LABEL to help in automation. In LABEL we specify a key value pair that can be later used for programmatically handling the Dockerfile. 
  • RUN: We use RUN command to execute any instructions in a new layer on top of the current image. With each RUN command we add something on top of the image and use it in subsequent steps in Dockerfile. 
  • CMD: We use CMD command to provide default values of an executing container. In a Dockerfile, if we include multiple CMD commands, then only the last instruction is used.

Ques: 17. Can you explain the basic Docker usage workflow?

  1. Everything starts with the Dockerfile. The Dockerfile is the source code of the Image. 
  2. Once the Dockerfile is created, you build it to create the image of the container. The image is just the "compiled version" of the "source code" which is the Dockerfile. 
  3. Once you have the image of the container, you should redistribute it using the registry. The registry is like a git repository -- you can push and pull images. 
  4. Next, you can use the image to run containers. A running container is very similar, in many aspects, to a virtual machine (but without the hypervisor).

Ques: 18. What are some similarities between Virtual Machine & Docker ?

Ans: Docker is not just like a Virtual Machine. It uses the host kernel & can’t boot a different operating system. So 5 similarities between Docker & VIrtual Machine can be:

Virtual Machine
Process in on VM cant see processes in other VMs
Process in one container cant see processes in other container
Each VM has its own root filesystem

Each container has its own root file system (Not Kernal)

Each VM gets its own virtual network adapter

Docker can get virtual network adapter. It can have  separate IP and ports

VM is a running instance of physical files(.VMS and .VMDK)

Docker containers are running instances of Docker Image

Host OS can be difference from guest OS

Host OS can be different from Container OS

Ques: 19. What are some of the differences between Docker container & Virtual Machine?

Ans: The differences between docker container and virtual machines are following:

Virtual Machine

Each Virtual Machine runs its own OS.

All containers share the same kernel of the host.
Boot up time is in minutes.
Containers instantiate in seconds.
Virtual Machines snapshots are used sparingly.

Images are build incrementally on top of another like layers. Lots operating system images/snapshots.
Not effective diffs.Not version controlled.

Images can be diffed and can be version controlled.Dockerhub is like GITHUB.

Cannot run more than couple of VMs on an average laptop.
Can run many Docker containers in a laptop.

Only one VM can be started from one set of VMx and VMDK files.

Multiple Docker containers can be started from one Docker image.

Ques: 20. Can I use JSON instead of YAML for my Docker Compose file? 

Ans: Yes. YAML is a superset of json so any JSON file should be valid YAML. To use a JSON file with Compose, specify the filename to use, for example:
 docker-compose -f docker-compose.json up

You can use json instead of YAML for your compose file, to use json file with compose, specify the filename to use.

Top 20 Oracle SCM Interview Questions and Answers


Ques: 1. What is the difference between ‘Accrue On Receipt’ and ‘Accrue at Period End’?


Accrue On Receipt means that when a receipt is saved, accrual transactions are immediately recorded and sent to the general ledger interface. This is also known as “online” accruals.

Accrue at Period End means that when a receipt is saved, the accrual transactions are not immediately recorded and sent to the general ledger; instead, the accounting entries are generated and sent at the end of the month by running the Receipt Accruals – Period-End Process.

All items with a destination type of either Inventory and Outside Processing are accrued on receipt. For items with a destination type of Expense, you have the option of accruing on receipt or at period end.


Oracle Fusion Applications interview Questions and Answers

Ques: 2. How many Key Flex Fields are there in inventory?


Seven KFF are there in Inventory:

  1. Account Alias 
  2. Item 
  3. Item Category 
  4. Item Catalogues 
  5. Stock Locators 
  6. Sales Order 
  7. Service Items


Oracle Accounts Payables Interview Questions and Answers


Ques: 3. What is the significance of the Document Total and Account Range types on the Approval Groups form?


The Document Total type sets the maximum limit for any approval actions taken by the user whom the approval group applies to. If multiple Document Totals are specified, the restriction will be to the Document Total, which is the lowest. 

The Account Range also allows for a document total which is then tied to a specific range of accounts listed on the same line. It is possible to have different account ranges with different amount Limits. This allows the same user to have a different dollar/account limit. 

It is mandatory to have an account range specified in each approval group defined. By default, if there is not an account range defined, all accounts will then be excluded from the document approval process, which means that the documents will not have an ability to become approved.


Oracle ADF Interview Questions and Answers                                 


Ques: 4. How an requisition line with item number and without item number [one time item] be combined to single document line in autocreate?


If you want to combine two requisition lines for the same item, one with an item number and one without, you have to manually autocreate the document and use Modify on the Tools menu to add the predefined item to the requisition line for the one time item.


Oracle Access Manager Interview Questions and Answers


Ques: 5. What is the difference between Purchased and Purchasable Flag for an item?


  • Purchasable is a status attribute flag, so based on this flag, certain transactions can be controlled for an item. 
  • Purchased flag decides whether to purchase and receive this item. 
  • Purchasable flag decides whether to order this item in a purchase order. 
  • If purchasable is enabled, item can be ordered in a purchase order, if not, new purchase orders can’t be created and approved for the items. 
  • If purchased is enabled, item can be received if already present in an approved purchase order.

Oracle Fusion HCM Interview Questions and Answers

Ques: 6. I am using encumbrance accounting and when I forward a Purchase Order for approval, I am encountering the following error: APP-14166: Please enter a forward to employee or funds are not reserved. How would you resolve it?


You must check the Reserve Funds check box when forwarding and/or approving a Purchase Order if you are using encumbrance. You can check to see if you are using encumbrance in Purchasing by doing the following:

1. Setup/Organizations/Financial Options
2. Change the Alternate Region to Encumbrance and see if the Use PO Encumbrance check box is checked.
3. Refer Note 1064155.6 for more details.


Oracle Financials Interview questions and Answers


Ques: 7. What are Reminder notifications?


Once an approver doesn’t respond to approval notification for quite sometime, then a reminder notification can be sent out to the approver. You can send up to two reminders to an approver using the Timeout feature. You can also specify that after a certain period of time, the document be forwarded automatically to the next approver in the hierarchy. This feature has to be setup by you by changing the PO and/or Requisition approval workflow in Oracle Workflow Builder.


Oracle Cloud Interview Questions and Answers

Ques: 8. What is the significance of “PO: Convert Requisition UOM to Source Document UOM” profile option?


Earlier in Autocreate if the requisition UOM is different from the BPA UOM the user would not be allowed to create a release. But in Create releases program this was possible. To make the behavior consistent we have introduced this profile option. If this profile is set to yes we allow the autocreation of the release with the quantity and UOM converted to that of the BPA. If the profile is set to yes we do not allow the creation of the req both in autocreate as well as the create releases program.

Oracle PL/SQL Interview Questions and Answers


Ques: 9. What are the difference in Lot and Serial?


Lot control is to control a whole batch of items. for example, in drug industry we have batch number which can be controlled using lot where we can track the complete batch using specific data.

Serial control is to monitor and track every single qty of an item like electronic devices where we track by serial number.

Oracle SQL Interview Questions and Answers


Ques: 10. What is the difference between the agreed amount and the amount limit fields while entering a contract purchase agreement and issues related to these fields?


i) The agreed amount field at the header level is copied to the amount limit in the terms and conditions block. This is also the amount that is printed on the blanket agreement and represents the contract amount between you and the vendor.

ii)The amount limit field will restrict the cumulative releases applied to this purchase agreement from exceeding the specified dollar amount entered here. The value of this field must be equal to or greater than the agreed amount field. This column is used for release approval amount validation. If the total cumulative releases exceed this amount approval will fail. The purpose of this field is to allow user to set a higher approval amount limit than the amount agreed.

Oracle RDMS Interview Questions and Answers


Ques: 11. How Warehouse Management System (WMS) is helpful compared to Inventory?


Warehouse Management (WMS) enables companies to maximize their utilization of labor, space and equipment investments by coordinating and optimizing resource usage and material flows. Specifically designed to support the needs of distribution, manufacturing, asset-intensive, and service businesses, Oracle WMS provides a single-platform across your entire global supply chain.

BI Publisher Interview Questions and Answers


Ques: 12. Why is there no category displayed or list of values for the category field in the purchase order you are creating?


You must also create category codes for your items. Then create a Category set for Purchasing controlled at the master level. Assign your items to a category code and the Purchasing category set you have created. Confirm that in Default Category Sets the Purchasing application points to the Purchasing Category set. This will populate the category and description when the item number is selected at the PO line level.

Oracle 10g Interview Questions and Answers 


Ques: 13. When the charge account field is non updateable?


In the following cases the charge account field is not updateable:

1. If the destination type code is INVENTORY or SHOP FLOOR.
2. If the distribution is already encumbered.
3. If the PO is created from a encumbered Requisition
4. If the destination type code is Expense and

If the project is entered and the profile option PA_ALLOW_FLEXBUILDER_OVERRIDES is set to NO. If the expense accrual code= RECEIPT


Ques: 14. How many Transaction Types exist?


Receive – Receive the items into Receiving Dock.
Deliver – Deliver the items into expense or inventory destination.
Return to Vendor – Return the received items directly to vendors.
Return to Receiving – Return the delivered items to Receiving Dock or inspection.
Accept – Accept items following an inspection.
Reject – Reject items following an inspection.
Transfer – Transfer items between locations.
Correct – Enter a positive or negative adjustment to a receiving or delivery transaction.
Match – Match unordered receipts to purchase orders.
Unordered – Receive items without purchase orders


Ques: 15. What is a Sub Inventory?


Sub inventories can be defined as:

Subinventiries are unique physical or logical separations of material inventory. These can be raw material, finished goods or defective material sub inventory. You must define at least one sub inventory. 

Sub inventories are of two types: storage and receiving.

  • Storage sub inventories are intermediate, or final put away locations for material. Material that resides in a storage sub inventory appears in on hand quantity and is tracked by the system. The system can book orders against and use manufacturing processes on material that resides in a storage sub inventory. You must define at least one storage sub inventory for your implementation. 
  • Receiving type sub inventory is only used for receiving items. Items in this sub inventories cannot be on-hand or reserved.


Ques: 16. How are Lot and Serial Numbers handled in Inter-Organization Transfers?


When you perform an inter organization transfer, the source and destination organization may have different lot/serial controls. Purchasing handles this situation as follows:

1. When the source organization uses controls and the destination organization does not, the control numbers are recorded as being issued from the source organization. Lot/serial transactions are recorded for the destination organization.

2. When the source organization does not use controls and the destination organization does, the transaction is processed normally.

3. When both source and destination organizations use controls, the control numbers are recorded as being issued from the source organization. These control numbers are tracked to insure that the same control numbers that were shipped are the ones
that are received. When items are returned from inventory to receiving or to the supplier, only the control numbers originally recorded for the delivery transaction can be used.


Ques:17. What is Pay On Receipt?


Pay on Receipt (also known as ERS (Evaluated Receipt Settlement) or Self-Billing) is an Oracle Purchasing’s concurrent program, which automatically creates invoices in Oracle Payables and matches them with PO’s automatically for the received amount. The short name for the program is POXPOIV.


Ques: 18. How can you have specific Requestor defaulted on Requisition form?


In order to have a specific requestor default onto the requisitions form, the user will have to set the following in the user’s requisition preferences. 

Navigation: /Purchasing -> Requisitions -> Requisitions Go to special ->preferences 

  • Click in the requestor field Choose a requestor from the list of values Click the ‘apply’ button, a message ‘ new preferences now in effect.’ 
  • Close the requisitions form Re-open the requisitions form Click in the lines region, the requestor from requisition preferences should appear in the requestor field. 
  • The requisition preferences are only valid while working on it , user needs to re enter requisition preferences each time he starts the applications.


Ques: 19. How does the Payment due days calculated if 30 days means will it be from invoice date or material receiving date?

Answer: Due days calculation is based on what you set up in the PAYMENT tab window of Supplier Master form.

It has Four options:

1. Goods Received
2. Invoice
3. Invoice received
4. System


Ques: 20.. Is it possible to have all requisitions created from Inventory – Min-Max Planning to be imported with a status of INCOMPLETE?


Yes, it is possible to have all requisitions created from Min-Max Planning with a status of INCOMPLETE. If the desired outcome is Min-Max requisitions showing a status of INCOMPLETE, it is necessary to set the profile option: INV: MinMax Reorder Approval to Incomplete. Conversely, if this profile option is set to Approved, all requisitions imported from Min-Max Planning will be imported with an approval status based on the approval authority of the user initiating the Requisition Import process.