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amazon-rds interview questions

Top amazon-rds frequently asked interview questions

AWS Elastic Beanstalk change RDS Endpoint

How do I change the configured RDS endpoint of an AWS Elastic Beanstalk environment? E.g. after the RDS database was deleted or should be replaced with a new RDS database.


Source: (StackOverflow)

Do I need Amazon's EC2, Cloudfront, RDS?

I want to publish a web site on Amazon's servers, that:

  1. Runs CakePHP
  2. Uses MySQL to store data
  3. Lets users upload audio through flash (currently using a hosted Flash Media Server), and listen to the files later

Do I need Amazon's EC2 for the website, RDS for the MySQL database, and CloudFront for the FMS? I'd really like a walkthrough of which services I should use.

Thanks.


Source: (StackOverflow)

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download RDS snapshot

I recently downgraded my EC2 instance. I can no longer connect to RDS. I think it might be that the internal IP is different and now the logins are attached to that specific IP. I haven't been able to figure it out. I would like to be able to get a backup from the snapshot. Is there a way to download it through AWS?


Source: (StackOverflow)

What are the respective advantages/limitations of Amazon RDS vs. EC2 with MySQL?

I realize a couple of basic differences between the two, i.e.

  1. EC2 is going to be cheaper

  2. RDS I wouldn't have to do maintenance

Other than those two, are there any advantages to running my database from RDS as opposed to a separate EC2 server acting as a MySQL server. Assuming similar instance sizes, are both going to run into the same limitations in terms of being able to handle a load?

To give you a little bit more info about my use, I've got a database, nothing too big or anything (biggest table 1 million rows), just high SELECT volume.


Source: (StackOverflow)

Amazon RDS - Online only when needed?

I had a question about Amazon RDS. I only need the database online for about 2 hours a day but I am dealing with quite a large database at around 1gb.

I have two main questions:

  1. Can I automate bringing my RDS database online and offline via scripts to save money?

  2. When I put a RDS offline to stop the "work hours" counter running and billing me, when I bring it back online will it still have the same content (i.e will all my data stay there, or will it have to be a blank DB?). If so, is there any way around this rather than backing up to S3 and reimporting it every time?


Source: (StackOverflow)

Has anyone figured out how to scale Amazon RDS read replicas?

I've recently set up a read replica to take some of the read load off of my Amazon multi-AZ RDS instance. The Amazon documentation clearly states that it is "up to your application to determine how read traffic is distributed across your read replicas".

Has anyone figured out a manageable way to scale read replicas? It doesn't seem like a very extensible solution to have different parts of my application hard-coded to read from specific replicas. Is there a way to set this up that is analogous to putting EC2 instances behind a load balancer?


Source: (StackOverflow)

Are Amazon RDS instances upgradable?

Will I am able to switch (I mean upgrade or downgrade) Amazon RDS instance on need basis or do I have to create a new afresh and go through migration?


Source: (StackOverflow)

How to 'switch' from MySQL to Amazon RDS with minimal application impact?

Amazon officially states: "Amazon RDS gives you access to the full capabilities of a familiar MySQL database. This means the code, applications, and tools you already use today with your existing MySQL databases work seamlessly with Amazon RDS."

I don't get this. Amazon RDS is accessible via web services and there a client libraries (like the one for .Net).

So if I have an existing .Net application that uses a DAL which in turn queries MySQL, how can I make the same DAL talk to the Amazon RDS (via the web services). Or am I missing something here?


Source: (StackOverflow)

Can I CREATE TRIGGER in an rds DB?

I'm trying to create a trigger on a table in my Amazon RDS database, and I can't seem to make it happen.

I tried to create a trigger on a table in the mysql client I use (Navicat), and got the error that I needed the SUPER privilege to do so. After some searching, I found that you could SET GLOBAL log_bin_trust_function_creators = 1 to get around this. I tried that using these instructions: http://getasysadmin.com/2011/06/amazon-rds-super-privileges/ (and then restarting the DB server for good measure), but no luck.

I also tried creating the trigger and setting the variable via the mysql commmand line to make sure Navicat wasn't adding anything unwanted to my sql commands, but that failed, too. It also seems from searching that there's no way to grant yourself the SUPER privilege.

So ... is creating a trigger possible in RDS?


Source: (StackOverflow)

how to run command "mysqladmin flush-hosts" on Amazon RDS database Server instance?

I got a database server failure, says host is blocked because of many connection errors. It ask me to unblock with 'mysqladmin flush-hosts'

how and where should I run this command to our amazon rds database server?

thank you


Source: (StackOverflow)

Creating A New MySQL User In Amazon RDS Environment

I need to create a new MySQL user with limited permission on an existing Amazon RDS instance. After encountering a couple error messages I was sort of able to do this using the official MySQL Administrator tool and the user now appears in the list. However, I'm unable to assign any schema privileges as all the users are greyed out. I'm logged in as the "master user" created when the instance was launched. Not sure where to go from here. I do have the RDS command line tools installed but wasn't able to track down anything there either. Ideas


Source: (StackOverflow)

How to set database timezone for a AWS RDS instance [duplicate]

This question already has an answer here:

We use the latest MySQL server on the AWS RDS instance and we have configured to run it on US-East data center. We are assuming that any new Date() or Time.now() invocation will store the date in the timezone in which the database server is running.

Is there a way to point my AWS RDS instance running on US-East to point to the PST timezone, so that any persistence of date will store the values in PST instead of EST. (i.e. If store an object around 10 AM EST, the db column should reflect 7 AM EST instead).


Source: (StackOverflow)

Explain this memory consumption pattern in Amazon RDS/Mysql?

Folks,

Can someone explain this memory consumption pattern on Amazon RDS running Mysql? In this graph, I upgraded to a db.m2.2xlarge, with 34GB of available memory, at 03:30. You can see the switchover very clearly. As clients start connecting and hitting that instance, the Freeable memory drops steeply to 5GB, where it is now hovering. On my previous upgrade between DB instance sizes, I saw the same pattern, until the freeable memory dropped to just under 1GB and hovered there indefinitely.

What is this instance doing between 03:30 and 07:30? Why isn't it freeing unused memory as it becomes available? I guess I would expect this graph to be a wave shape, corresponding to usage and traffic patterns, vs and exponential decay shape, which suggests that it's a super lazy and/or broken garbage collection algorithm.

Also note that about 2/3rds of DB operations are writes and 1/3 are reads, and there is about 2GB of memcache in front of the DB.

memory consumption amazon rds mysql


Source: (StackOverflow)

Using PHPMyAdmin to administer Amazon RDS

I can't get PHPMyAdmin to connect to my Amazon RDS instance. I've granted permissions for my IP address to the DB Security Group which has access to this database I'm trying to access. Here's what I'm working with...

    $cfg['Servers'][$i]['pmadb'] = $dbname;
    $cfg['Servers'][$i]['bookmarktable'] = 'pma_bookmark';
    $cfg['Servers'][$i]['relation'] = 'pma_relation';
    $cfg['Servers'][$i]['table_info'] = 'pma_table_info';
    $cfg['Servers'][$i]['table_coords'] = 'pma_table_coords';
    $cfg['Servers'][$i]['pdf_pages'] = 'pma_pdf_pages';
    $cfg['Servers'][$i]['column_info'] = 'pma_column_info';
    $cfg['Servers'][$i]['history'] = 'pma_history';
    $cfg['Servers'][$i]['designer_coords'] = 'pma_designer_coords';

    /* Uncomment the following to enable logging in to passwordless accounts,
     * after taking note of the associated security risks. */
    // $cfg['Servers'][$i]['AllowNoPassword'] = TRUE;

    /* Advance to next server for rest of config */
    $i++;
}

    $cfg['Servers'][$i]['auth_type'] = 'http';  //is this correct?
    $cfg['Servers'][$i]['user'] = 'MASTER-USER';
    $cfg['Servers'][$i]['password'] = 'MASTER-USER-PASSWORD';
    $cfg['Servers'][$i]['hide_db'] = '(mysql|information_schema|phpmyadmin)';
    /* Server parameters */
    $cfg['Servers'][$i]['host'] = 'MY-DB.us-east-1.rds.amazonaws.com';
    $cfg['Servers'][$i]['connection_type'] = 'socket';
    $cfg['Servers'][$i]['port'] = PORT;

I'm not sure if my configuration is correct...

I'm getting this error: #2013 - Lost connection to MySQL server at 'reading initial communication packet', system error: 110

Anyone have any advice?


Source: (StackOverflow)

How to connect to Amazon RDS via SSL?

I'm trying to set up an SSL connection to a MySQL database hosted via Amazon RDS. I'm confused as to how to connect.

According to Amazon's documentation, I need to download a CA certificate called "rds-ca-2015-root.pem" and use it in my SSL connection. I set the database user that I am connecting with to require SSL.

In PHP, I include the code below to initiate the connection:

$mysqli = mysqli_init();
mysqli_options($mysqli, MYSQLI_OPT_SSL_VERIFY_SERVER_CERT, true);
$mysqli->ssl_set(NULL, NULL, "/path/to/pem", NULL, NULL);
$mysqli->real_connect("host", "username", "password", "name", 3306, NULL, MYSQLI_CLIENT_SSL);

However, no matter which path I specify as the third parameter in ssl_set() (even if the path is invalid), an SSL connection is successfully made. The third parameter just can't be set to NULL.

I verify this by running this query: SHOW STATUS LIKE 'Ssl_cipher';. The output verifies that the connection is encrypted (Ssl_cipher => AES256-SHA).

Could someone please explain to me how this works? I am confused as to why the connection continues to work successfully when the path is incorrect. How is the RDS server being verified?


Source: (StackOverflow)