Apache Storm Interview Questions for Freshers Part – 2

Frequently Asked Apache Storm Interview Questions Part – 2

Explain When To Use Field Grouping In Storm? Is There Any Time-out Or Limit To Known Field Values?

Field grouping in storm uses a mod hash function to decide which task to send a tuple, ensuring which task will be processed in the correct order. For that, you don’t require any cache. So, there is no time-out or limit to known field values.

The stream is partitioned by the fields specified in the grouping. For example, if the stream is grouped by the “user-id” field, tuples with the same “user-id” will always go to the same task, but tuples with different “user-id”‘s may go to different tasks.

What Is Mod_vhost_alias?

This module creates dynamically configured virtual hosts, by allowing the IP address and/or the Host: header of the HTTP request to be used as part of the path name to determine what files to serve. This allows for easy use of a huge number of virtual hosts with similar configurations.

Tell Me Is Running Apache As A Root Is A Security Risk?

No. Root process opens port 80, but never listens to it, so no user will actually enter the site with root rights. If you kill the root process, you will see the other roots disappear as well.

What Is Multiviews?

MultiViews search is enabled by the MultiViews Options. It is the general name given to the Apache server’s ability to provide language-specific document variants in response to a request.

This is documented quite thoroughly in the content negotiation description page. In addition, Apache Week carried an article on this subject entitled It then chooses the best match to the client’s requirements, and returns that document.

Does Apache Include A Search Engine?

Yes, Apache contains a Search engine. You can search a report name in Apache by using the “Search title”.

Explain How You Can Streamline Log Files Using Apache Storm?

To read from the log files, you can configure your spout and emit per line as it read the log. The output then can be assign to a bolt for analyzing.

Mention How Storm Application Can Be Beneficial In Financial Services?

In financial services, Storm can be helpful in preventing

Securities fraud :

Perform real-time anomaly detection on known patterns of activities and use learned patterns from prior modeling and simulations.
Correlate transaction data with other streams (chat, email, etc.) in a cost-effective parallel processing environment.

Reduce query time from hours to minutes on large volumes of data.

Build a single platform for operational applications and analytics that reduces total cost of ownership (TCO)

Order routing :

Order routing is the process by which an order goes from the end user to an exchange. An order may go directly to the exchange from the customer, or it may go first to a broker who then routes the order to the exchange.

Pricing :

Pricing is the process whereby a business sets the price at which it will sell its products and services, and may be part of the business’s marketing plan.

Compliance Violations :

compliance means conforming to a rule, such as a specification, policy, standard or law. Regulatory compliance describes the goal that organizations aspire to achieve in their efforts to ensure that they are aware of and take steps to comply with relevant laws and regulations. And any disturbance in regarding compliance is violations in compliance.

Can We Use Active Server Pages(asp) With Apache?

Apache Web Server package does not include ASP support. However, a number of projects provide ASP or ASP-like functionality for Apache.

Some of these are:

Apache:ASP :-

Apache ASP provides Active Server Pages port to the Apache Web Server with Perl scripting only, and enables developing of dynamic web applications with session management and embedded Perl code. There are also many powerful extensions, including XML taglibs, XSLT rendering, and new events not originally part of the ASP AP.

mod_mono :-

It is an Apache 2.0/2.2/2.4.3 module that provides ASP.NET support for the web’s favorite server, Apache. It is hosted inside Apache. Depending on your configuration, the Apache box could be one or a dozen of separate processes, all of these processes will send their ASP.NET requests to the mod-mono-server process.

The mod-mono-server process in turn can host multiple independent applications. It does this by using Application Domains to isolate the applications from each other, while using a single Mono virtual machine.

Explain What Is Toplogy_message_timeout_secs In Apache Storm?

It is the maximum amount of time allotted to the topology to fully process a message released by a spout. If the message in not acknowledged in given time frame, Apache Storm will fail the message on the spout.

Mention The Difference Between Apache Kafka And Apache Storm?

Apache Kafka :

It is a distributed and robust messaging system that can handle huge amount of data and allows passage of messages from one end-point to another. Kafka is designed to allow a single cluster to serve as the central data backbone for a large organization.

It can be elastically and transparently expanded without downtime. Data streams are partitioned and spread over a cluster of machines to allow data streams larger than the capability of any single machine and to allow clusters of coordinated consumers.

Whereas.

Apache Storm :

It is a real time message processing system, and you can edit or manipulate data in real-time. Storm pulls the data from Kafka and applies some required manipulation. It makes it easy to reliably process unbounded streams of data, doing real-time processing what Hadoop did for batch processing. Storm is simple, can be used with any programming language, and is a lot of fun to use.

What Is Servertype Directive In Apache Server?

It defines whether Apache should spawn itself as a child process (standalone) or keep everything in a single process (inetd). Keeping it inetd conserves resources.

The ServerType directive is included in Apache 1.3 for background compatibility with older UNIX-based version of Apache. By default, Apache is set to standalone server which means Apache will run as a separate application on the server. The ServerType directive isn’t available in Apache 2.0.

In Which Folder Are Java Application Stored In Apache?

Java applications are not stored in Apache, it can be only connected to a other Java webapp hosting webserver using the mod_jk connector. mod_jk is a replacement to the elderly mod_jserv. It is a completely new Tomcat-Apache plug-in that handles the communication between Tomcat and Apache.

Several reasons:

mod_jserv was too complex :

Because it was ported from Apache/JServ, it brought with it lots of JServ specific bits that aren’t needed by Apache.

mod_jserv supported only Apache :

Tomcat supports many web servers through a compatibility layer named the jk library. Supporting two different modes of work became problematic in terms of support, documentation and bug fixes. mod_jk should fix that.

The layered approach :

provided by the jk library makes it easier to support both Apache1.3.x and Apache2.xx.

Better support for SSL :

mod_jserv couldn’t reliably identify whether a request was made via HTTP or HTTPS. mod_jk can, using the newer Ajpv13 protocol.