• Call: +1 (858) 429-9131

Posts Tagged ‘S3’

“IAM user, who can write to the S3 bucket”

Here we are to educate ourselves as to what “IAM user, who can write to the S3 bucket” is, by using cloudfront distribution and S3 objects, which are of world readable.

 

1.Create a bucket in s3 my-bucket

1. Log in to the AWS Management Console

2. Click on s3 tab

3. Create a new bucket

4. Create a custom/aws bucket policy to make it world readable

Read more…

Splunk on AWS EC2 CloudSplunk

Whats is Splunk ?

Splunk is a log, monitoring and reporting tool for IT system administrators with search capabilities. It crawls logs, metrics, and other data from applications, servers and network devices and indexes it in a searchable repository from which it can generate graphs, SQL reports and alerts. Splunk can be easily set on the AWS machine archival storage as EBS volumes and periodically syncing the archive from EBS to S3 Bucket or taking EBS snapshots for backup of the logs for the future use.

Generally its hard to track the logs from the server. We do have different monitoring tools such as Nagios, Zabix, here is a new tool named Splunk, which is a kind of bigger solution for providing monitor the visibility inside all the dynamic and complex environment. For example you have an application seems to be very slow, its not because the app have some issue , its because of the lack of free memory on the server. Such kind of details can be obtained from inside the splunk server.

Why do we go for Splunk ?

In auto-scaled where the instances are running under load-balancer scenarios, the servers gets scale up and down, and also there are some situations like some instance gets terminated without any alert. During this situation it will be good to get the login sessions during the server-down state, also the server access logs, so that we can track the reason for the server down. Managing logs on server is really hard, and also the logs will be available on different location. Inorder to address this problem, here we have setup Splunk to listen on a TCP port for any network traffic passes all others servers log to this host, then you will have a centralized, indexed log repository for all of your services.

Here i will guide you on deploying the splunk on the AWS EC2 and configuring splunk forwarder on the remote machine. Splunk is very flexible and is easy to install on any servers. You can select the appropriate hardware capacity planning for your Splunk deployment from here.

Once you have installed the Splunk server , follow the steps given below to start the app:

Now start the Splunk using the command given below:
[NOTE: The here Splunk is installed in /opt location]

/opt/splunk/bin/splunk start

Now you can access the Splunk web UI using the URL given below:

http://domain.com:8000

The Splunk need to be configure in such a way that it should be able to receive the data from the remote machine. For this you will need is to follow the following steps:

1. Login to Splunk WebUI eg. http://10.10.10.35:8000
2. Go to Manager –> Forwarding and receiving –> Receive data
3. Click on New Button and add default port i.e. 9997
4. Click on save button to save the settings.
NOTE: Make sure that the port is opened for the server to accept the data from the remote machine.

Next you will need to install Splunk forwarder on the remote machine. Once you have installed the forwarder start the app as shown below:

/opt/splunk/bin/splunk start

Then enable the forwarder using the command and restart the Splunk app.

./splunk enable app SplunkLightForwarder -auth
Splunk username: admin
Password: changeme
./splunk add forward-server 10.10.10.35:9997 -auth admin
./splunk restart

Now after few minutes you can see the Splunk dashboard indexes all it logs on the realtime dashboard.

Generally in Splunk deployment , we have a deployment server which pushes the configuration on to the deployment client, grouped into server class. The Splunk deployment server is a centralized manager which manages several splunk instances known as deployment client. The deployment client is the Splunk instance installed on the remote machine and parse the log on to the Splunk deployment server.

 

 

The Splunk generally collects the data from the remote machine which contain  the machine-to-machine and also from human-to-machine interaction. With these collected data it indexes to the engine and generates the reports and also drives alert. The email alert can be configured for the specific conditions like. For example we can configure the alert mail when it finds any log containing the error messages. The Splunk will access all these large volume of data and also provides the visibility and intelligence to IT and data ware house. And also will be able to perform the real-time and historic analysis of all the bulk data from the remote machine.

Its easy to use, also to install and also easier deploy method make this application different from others. The Splunk will be very useful for the developer team for finding and fixing the bugs and also helps to provide real time insights.

Achieving HIPAA on AWS / EC2 with Windows Server 2008

When you are creating a HIPAA compliant system on cloud service like AWS / EC2 / S3, you have to carefully examine the different levels of data security provided by the Cloud Service provider

At a minimum level, the following should be ascertained:

i) Where is the Cloud provider’s data center physically located. In some countries, HIPAA restricts Protected Health Information ( PHI ) to be stored on servers located outside of the country.

ii) Whether the cloud provider contractually obligated to protect the customer’s data at the same level as the customer’s own internal policies?

iii) Cloud provider’s Backup and Recovery policies

iv) What are the provider’s policies on data handling/management and access control? Do adequate controls exist to prevent impermissible copying or removal of customer data by the provider, or by unauthorized employees of the company?

v) What happens to data when it is deleted? This is very important as customers will be storing data on virtual Machines. Also What happens to cloud hardware when the hardware is replaced?

In this blog we are only looking at the different security levels to be taken by the application developer to make sure that a web application built on AWS / EC2 using Windows Server 2008 / .NET / MSSQL / IIS 7 / is HIPAA compliant. The basic requirement is to encrypt all the data at rest and transit

1. Encrypting Data in transit between the user ( clients ) and the server ( Webserver )

SSL over HTTP ( HTTPS )

Steps used to Implement SSL on IIS are the following:

[bash]
1.Open IIS Manager.
2.Click on the server name.
3.Double-click the “Server Certificates” button in the “Security” section
4.Click on self-signed certificate
5.Enter certificate name and click ok
6. Select the name of the server to which the certificate was installed.

7. From the “Actions” menu (on the right), click on “Bindings.” This will open the “Site Bindings” window

8. In the “Site Bindings” window, click “Add” This will open the “Add Site Binding” window

9. Under “Type” choose https. The IP address should be the IP address of the site , and the port over which traffic will be secured by SSL is usually 443. The “SSL Certificate” field should specify the certificate that was installed in step 5.

10.Click “OK.” . SSL is now installed .
[/bash]

2 ) Encrypting Data at Rest ( Document Root )

EFS with IIS

You can use EFS ( Encrypted File System ) in Windows 2008 Server to automatically encrypt your data when it is stored on the hard disk.

Encrypt a Folder:

[bash]
1. Open Windows Explorer.
2. Right-click the folder that you want to encrypt , and then click Properties.
3. On the General tab, click Advanced.
4. Under Compress or Encrypt attributes, select the Encrypt contents to secure data check box and then click OK.
5. Click OK.
6. In the Confirm Attribute Changes dialog box that appears, use one of the following steps:
i) If you want to encrypt only the folder, click Apply changes to this folder only, and then click OK.
ii) If you want to encrypt the existing folder contents along with the folder, click Apply changes to this folder, subfolders and files, and then click OK.
[/bash]

The folder becomes an encrypted folder. New files that you create in this folder are automatically encrypted


3 ) Encrypting MSSQL Database ( Data at Rest )

TDE ( Transparent Data Encryption )

TDE is a new feature inbuilt in MSSQL Server 2008 Enterprise Edition . Data is encrypted before it is written to disk; data is decrypted when it is read from disk. The “transparent” aspect of TDE is that the encryption is performed by the database engine and SQL Server clients are completely unaware of it. There is absolutely no code that needs to be written to perform the encryption and decryption .So there is no need for changing any code ( Database Queries ) in the Application .

STEPS

i) Create a Master Key

A master key is a symmetric key that is used to create certificates and asymmetric keys. Execute the following script to create a master key:

[bash]
USE master;
CREATE MASTER KEY
ENCRYPTION BY PASSWORD = ‘Pass@word1’;
GO
[/bash]

ii)Create Certificate

Certificates can be used to create symmetric keys for data encryption or to encrypt the data directly. Execute the following script to create a certificate:

[bash]
CREATE CERTIFICATE TDECert
WITH SUBJECT = ‘TDE Certificate’
GO
[/bash]

iii) Create a Database Encryption Key and Protect it by the Certificate

[bash]
1.Go to object explorer in the left pane of the MSSQL SERVER Management Studio
2.Right Click on the database on which TDE Requires
3.Click Tasks and Navigate to Manage Database Encryption
4. Select the encrytion algorithm (AES 128/192/256) and select the certificate you have created
5.Then Mark the check Box for Set Database Encryption On
[/bash]

You can query the is_encrypted column in sys.databases to determine whether TDE is enabled for a particular database.

[bash]
SELECT [name], is_encrypted FROM sys.databases
GO
[/bash]


4 ) Encrypting Data in transit between the Webserver and the MSSQL Database

MSSQL secure connection using SSL

i) Creating a self-singned cert using makecert
[bash]
makecert -r -pe -n “CN=YOUR_SERVER_FQDN” -b 01/01/2000 -e 01/01/2036 -eku 1.3.6.1.5.5.7.3.1 -ss my -sr localMachine -sky exchange -sp “Microsoft RSA SChannel Cryptographic Provider” -sy 12 c:\test.cer
[/bash]

ii) Install this cert

[bash]
Copy c:\test.cer into your client machine, run c:\test.cer from command window, select “Install Certificate”. -> click “Next” -> select “Place all certificates in the following store” –> click “Browser” -> select “Trusted Root Certification Authorities” -> select OK and Finish
[/bash]

iii) Open SQL Server Configuration Manager

[bash]
Expand SQL Server Network Configuration, right-click “Protocols for MSSQLSERVER” then click “properties”. On the “Certificate” tab select the certificate just installed . On the “Flags” tab, set “ForceEncryption” YES.
[/bash]

Now SSL is ready to be used on the server. The only modification needed in the .NET code is connection string. It will be

[bash]
connectionString=”Data Source=localhost;Initial Catalog=mydb;User ID=user1;Password=pas@123;Encrypt=true;TrustServerCertificate=true”
[/bash]

SSL for Tomcat on AWS EC2

To launch an AWS/EC2 instance, at first setting up a security group to specify what network traffic is allowed to reach the instance. Then select an AMI and launch an instance from it. And create a volume in the same zone of the instance and attach with it. Format the device and mount it to a directory. After that follow the steps to create SSL for Tomcat:

1. For the tomcat we need java, so create a directory to save the Java Binary file.

[shell] mkdir /usr/java
cd /usr/java [/shell]

2. Download jdk binary file (jdk-x-linux-ix.bin) here
Use URL http://www.oracle.com/technetwork/java/archive-139210.html

3. Execute the Binary file

[shell] /usr/java/jdk-x-linux-ix.bin [/shell]

Now we have the Java in our device. Then Download the Tomcat and install it followed by the instructions:-

1. Create a directory to save the tomcat

[shell] mkdir /usr/tomcat
cd /usr/tomcat [/shell]

2. Download tomcat source file (apache-tomcat-x.tar.gz) here
Use URL http://apache.hoxt.com/tomcat/tomcat-6/v6.0.32/bin/

3. Extract that file

[shell] tar -zxvf apache-tomcat-x.tar.gz [/shell]

4. Edit the catalina.sh file

[shell] vim /usr/tomcat/apache-tomcat-x/bin/catalina.sh [/shell]

[shell]

#** Add at the top **
JAVA_HOME=/usr/java/jdk1.x.x_x

[/shell]

save and exit
5. Start the tomcat

[shell] /usr/tomcat/apache-tomcat-x/bin/startup.sh [/shell]

6. We can see the logs by using the given command

[shell]tail -f /usr/tomcat/apache-tomcat-x/logs/catalina.out [/shell]

7. Take the browser and enter the URL http://localhost
Now we can see the tomcat index page

8. To stop the tomcat

[shell]/usr/tomcat/apache-tomcat-x/bin/shutdown.sh [/shell]

Now configure the SSL Certificate for tomcat. When you choose to activate SSL on your web server you will be prompted to complete a number of questions about the identity of your website and your company. Your web server then creates two cryptographic keys – a Private Key and a Public Key. The Public Key does not need to be secret and is placed into a Certificate Signing Request (CSR) – a data file also containing your details.

Create a self signed certificate authority (CA) and keystore.

1. Make a directory to hold the certs and keystore. This might be something like:

[shell] mkdir /usr/tomcat/ssl
cd /usr/tomcat/ssl [/shell]

2. Generate a private key for the server and remember it for the next steps

[shell]openssl genrsa -des3 -out server.key 1024[/shell]

Generating RSA private key, 1024 bit long modulus
…………………..++++++
…++++++
e is 65537 (0x10001)
Enter pass phrase for server.key:
Verifying – Enter pass phrase for server.key:

3. Generate a CSR (Certificate Signing Request). Give the data after executing this command

[shell]openssl req -new -key server.key -out server.csr[/shell]

Enter pass phrase for server.key:
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter ‘.’, the field will be left blank.
—–
Country Name (2 letter code) [GB]:
State or Province Name (full name) [Berkshire]:
Locality Name (eg, city) [Newbury]:
Organization Name (eg, company) [My Company Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server’s hostname) []:
Email Address []:

Please enter the following ‘extra’ attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

4. Remove the passphrasse from the key

[shell]cp server.key server.key.org
openssl rsa -in server.key.org -out server.key[/shell]

Enter pass phrase for server.key.org:
writing RSA key

5. Generate the self signed certificate

[shell]openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt[/shell]

Signature ok
subject=/C=GB/ST=Berkshire/L=Newbury/O=My Company Ltd
Getting Private key

You should then submit the CSR. During the SSL Certificate application process, the Certification Authority will validate your details and issue an SSL Certificate containing your details and allowing you to use SSL. Typically an SSL Certificate will contain your domain name, your company name, your address, your city, your state and your country. It will also contain the expiration date of the Certificate and details of the Certification Authority responsible for the issuance of the Certificate.

Create a certificate for tomcat and add both to the keystore

1. Change the path to ssl

[shell]cd /usr/tomcat/ssl[/shell]

2. Create a keypair for ‘tomcat’

[shell]keytool -genkey -alias tom -keyalg RSA -keystore tom.ks[/shell]

Enter keystore password:
Re-enter new password:
What is your first and last name?
[Unknown]:
What is the name of your organizational unit?
[Unknown]:
What is the name of your organization?
[Unknown]:
What is the name of your City or Locality?
[Unknown]:
What is the name of your State or Province?
[Unknown]:
What is the two-letter country code for this unit?
[Unknown]:

Is CN=Unknown, OU=Unknown, O=Unknown, L=Unknown, ST=Unknown, C=Unknown correct?
[no]: yes

Enter key password for <tom>
(RETURN if same as keystore password):
Re-enter new password:

3. Generate a CSR (Certificate Signing Request) for tomcat

[shell]keytool -keystore tom.ks -alias tom -certreq -file tom.csr[/shell]

Enter keystore password:

4. create unique serial number

[shell]echo 02 > serial.txt[/shell]

5. Sign the tomcat CSR

[shell]openssl x509 -CA server.crt -CAkey server.key -CAserial serial.txt -req -in tom.csr -out tom.cer -days 365[/shell]

Signature ok
subject=/C=Unknown/ST=Unknown/L=Unknown/O=Unknown/OU=Unknown/CN=Unknown
Getting CA Private Key

6. Import the server CA certificate into the keystore

[shell]keytool -import -alias serverCA -file server.crt -keystore tom.ks[/shell]

Enter keystore password:
Owner: O=My Company Ltd, L=Newbury, ST=Berkshire, C=GB
Issuer: O=My Company Ltd, L=Newbury, ST=Berkshire, C=GB
Serial number: ee13c90cb351968b
Valid from: Thu May 19 02:12:51 EDT 2011 until: Fri May 18 02:12:51 EDT 2012
Certificate fingerprints:
MD5: EE:F0:69:01:4D:D2:DA:A2:4E:88:EF:DC:A8:3F:A9:00
SHA1: 47:97:72:EF:30:02:F7:82:BE:CD:CA:F5:CE:4E:ED:89:73:23:4E:24
Signature algorithm name: SHA1withRSA
Version: 1
Trust this certificate? [no]: yes
Certificate was added to keystore

7. Add the tomcat certificate to the keystore

[shell]keytool -import -alias tom -file tom.cer -keystore tom.ks[/shell]

Enter keystore password:
Certificate reply was installed in keystore

To configure a secure (SSL) HTTP connector for Tomcat, verify that it is activated in the $TOMCAT_HOME/conf/server.xml file. Edit this file and add the following lines.

Tomcat configuration

1. Edit the given portion of tomcat configuretion file and change the port as 80

[shell]vim /usr/tomcat/apache-tomcat-6.0.13/conf/server.xml[/shell]

[shell]“””””” <Connector port=”8080″ protocol=”HTTP/1.1″
connectionTimeout=”20000″
redirectPort=”8443″ /> “”””””

<Connector port=”80″ protocol=”HTTP/1.1″
connectionTimeout=”20000″
redirectPort=”8443″ />

[/shell]

2. Add the given portion to server.xml and give your password in the password portion

[shell]

<Connector port=”443″ protocol=”HTTP/1.1″ SSLEnabled=”true”
maxThreads=”150″ scheme=”https” secure=”true”
keystoreFile=”tom.ks”
keystorePass=”password”
clientAuth=”false” sslProtocol=”TLS” />

[/shell]

When you start the Tomcat Your web server will match your issued SSL Certificate to your Private Key. Your web server will then be able to establish an encrypted link between the website and your customer’s web browser.

Start the tomcat with SSL Certificate

1. Restart tomcat

[shell]/usr/tomcat/apache-tomcat-6.0.13/bin/shutdown.sh
/usr/tomcat/apache-tomcat-6.0.13/bin/startup.sh[/shell]

2. Go to https://Public DNS name:443/

Then your browser shows a security issue. Click the Approve button. Then you can enter to the tomcat with your certificate. When a browser connects to a secure site it will retrieve the site’s SSL Certificate and check that it has not expired, it has been issued by a Certification Authority the browser trusts, and that it is being used by the website for which it has been issued. If it fails on any one of these checks the browser will display a warning to the end user letting them know that the site is not secured by SSL.

You are Done !!!

Deploying a load balanced e-commerce portal in Amazon EC2

Update: NFS should not be used as that will be a SPOF. One should use S3 or other object stores. An alternative could be multi-node GlusterFS if someone needs volumes shared across nodes.

When building an infrastructure for an eCommerce portal on Cloud, it is important to note that it should be available all the time, that it is fail safe with outages like the one we had recently in AWS EU and U.S. East Regions, survive Hardware failure or any other issues like bug in the system or deployment errors. We built an infrastructure on AWS Cloud that address all these issues with LAMP using various AWS Cloud services like EC2, S3, RDS, EBS etc. It is described in detail below:

 

Achieving High Availability & Fail over across Datacenters

Elastic Load Balancer (ELB)

The Elastic Loadbalancer ( ELB ) service provided by AWS tries to achieve the following:

(i) Spans across Datacenters: Loadbalance traffic across mulitple datacenters (AZ )thus providing high availability even if one datacenter goes down. So you should always make sure that when you launch instances under an ELB, you should launch it in different Availability zones. You can also launch instances in the same AZ but by default ELB will redirect request across multiple AZ in a Round Robin way.

(ii) Failover: ELB will periodically monitor the health of the instances and if any of the instance or monitored service ( e.g. Http ) goes down, ELB will stop redirecting requests to that instance and all the request will be redirected to the remaining number of instances registered under ELB. When the instance comes backup, it will again start redirecting requests to that instance.

(iii) Handling root domain ( apex / main domain ) and subdomains: ELB can loadbalance only those requests coming to alias / subdomain( www ). It cannot handle request coming to root domain. This is because when you configure DNS for enabling ELB, you can only set CNAME to ELB for subdomains. There are 2 reasons for this. One is when you configure ELB, you will only get a Public DNS name for the ELB like the following instead of a Public IP.

[bash]Test-1736333854.us-east-1.elb.amazonaws.com [/bash]

This is because AWS changes the Public IP of the ELB periodically for providing scalability for ELB itself. Another reason why you cannot redirect main domain request to ELB is that DNS protocol itself restricts the usage of CNAME or anything other than “A” record for a root domain. So you cannot CNAME root domain to ELB DNS name.

So for serving root domain requests with ELB , there are only work arounds like mentioned below:

a) We have to assign an elastic IP for an instance under ELB. But what if this instance goes down? Set heartbeat to switch EIP? This is a bit complicated setup as switching EIP to instances present across AZ takes time.

b)The other option is to have the root domain point to the IP addresses of the destination by configuring one or more “A” records (address records) for root domain. You can do that if you know the destination IP addresses are fixed, such as if you are using EC2 Elastic IP addresses. We wouldn’t recommend this because IP addresses will be cached at the client end for long time even if you set low value of TTL at the nameservers. This is because TTL value can also be configured at the the client end overriding the TTL value provided by the nameserver of the domain. e.g. with nscd ( Nameserver Caching Daemon) you can set the TTL value manually in its configuration file.

c) You can keep a separate web server not under ELB with a Redirect Rule for redirecting root domain requests to www. You should make sure that this webserver is highly available as well.

d) A better solution is to go for Domain Registrars ( DNS service providers ) who provide this feature of redirecting root domain requests to www. So this can be handled at the DNS itself. The DNS service provided by AWS “Route53” can be used for this ‘Zone apex’ ( root domain ) redirection.

(iv) SSL Termination

There is support for “SSL termination” in ELB which means you can use ELB to loadbalance HTTPS requests too. You just need to buy the SSL certificate and simply upload it to ELB. ELB will redirect all the HTTPS request to the backend servers. So you can make an eCommerce portal highly secure and highly available with ELB.

(v) Persistent Session

You can enable Sticky Session with ELB but the problem is users will be logged out if any of the instance / webserver goes down and ELB will redirect the subsequent requests from the same user to a different instance and it will prompt the user to login again. To tackle this there were few options we had considered –
a)You can either setup distributed failover memcached server or
b)You can use RDS for storing Session.

We went for RDS as our Session Management store since RDS is an excellent choice for Database Administration as well if you are using MySQL as the Database.

Your application must be configured to write session data to an RDS database. So when an instance / webserver goes down and when the ELB redirects the user request to a different instance, the user will not be asked to login again as all servers are reading session data from the same place that is RDS. The user won’t notice anything at all, even though they’ve now started talking to another server. We recommend using a Multi-AZ RDS instance and write session data into this. So if one of your EC2 instances goes down, the other instances will still have access to the RDS database, and likewise if an RDS zone goes down, Amazon fail this over to the second AZ internally, transparently to you and your application.

So the easiest and most reliable way to share sessions for failover on a multi-server environment is to use RDS, since Amazon handle the database layer’s failover for you.

So basically you can achieve two things by using RDS – Session management and Database Management.

 

AutoScaling

The Autoscaling service provided by AWS allows you to scale horizontally up / down with CPU usage, RAM, Disk I/O etc.

Ideally you should use a Base AMI with Autoscaling that will pull the required packages from a Centralized location like Chef Platform and code from the Version Control System or S3. You can write a startup script to run on instance bootup for this purpose. So when Autoscaling launches a new instance it will pull all the latest updated versions of the packages, code and also any other required custom configurations from a centralized location. This will also make it easier to manage all the configuration details, code updates from a centralized location using tools like Chef Platform, Version Control System or S3 respectively.

Apart from Centralised Configuration / Code management, the reason for using Base ami with Autoscaling is that it is not possible to change the ami configured with Autoscaling service dynamically.

 

Storage for Application Files

We came across lot of options for storing the application files. However you have to consider your priorities before you select a storage service for the code. Following are the points to consider for your application file storage system:

(i)Latency issues: All shared storage systems like NFS / GlusterFS / EBS / S3 etc have latency issues when compared to Instance store (Ephemeral Storage)

(ii)High availability: If you are using a shared storage service like NFS, it should never go down for the entire system to be available all the time.

(iii)Access to the code: How to get the latest code during incremental roll out of a new instance because if you are using a shared storage, it becomes difficult to gives access to the shared storage system when a new instance is launched

We went for instance store / ephemeral store that gives you better I/O performance. You can keep your own highly available SVN repository or go for publicly available Version Control Systems like GitHub. At the same time you can also keep a copy in S3 and sync to it whenever there is a code update. This will make it more redundant.

The problem with using shared storage service like NFS / GlusterFS with EBS / S3 is it becomes difficult to avoid single point failure for NFS / GlusterFS service. But if your site doesn’t have much hits and your priority becomes redundancy, you can go for mounting S3 as filesystem using tools like s3cmd and use that as a shared storage with NFS for multiple instance. The problem with S3 is that it is not intended to be used as a filesystem and there have been issues reported with speed and caching. Or you can use EBS volume for code storage if you have only a single instance serving the request. Even using NFS with EBS volumes ( with frequent snapshots to S3 ) gives better performance than using S3 as shared storage for files.

Not only does instance store gives you better performance, error rates very rare. with EBS volumes error rates are reported frequently. Recent outages with AWS EU & US East Regions shows that the down time was made worse due to increase in time taken to recover from EBS errors.

 

Code Deployment

For automating code deployment, you can configure deployment tools like Capistrano. This will become very handy when you have multiple servers to update simultaneously. Capistrano uses Ruby language and is built for Ruby code deployment but with little changes, you can automate deployment of PHP / Perl / Python / JAVA based application.

chef-deploy is another tool that comes with chef for automating code deployment. Continuous Integration tools like Hudson / Cruise Control are excellent tools when you want to automate the Build, Deployment, Test and Rollback process.

For code deployment, we follow a Release Management process where we keep a staging environment that is an exact replica of the production environment. We push code to the production environment only when it’s been completely tested in the staging environment and approved by the Release Manager. This will further reduce the errors / bugs / and downtime time caused due to the code release.

 

Database Server

We went for RDS across AZ for High availability. AWS will take care of Redundancy, Performance Optimisation, Scalability and Backup. You can avoid the hassle of managing a Database Server by using RDS. RDS is as an excellent distributed highly available Session Management System. You can also take regular backup from RDS and keep it in S3.

You can also use Master–Slave Replication setup instead of RDS. This is also a good option for achieving high availability for Database server. The challenging part will be to manually configure failover for both master and slave servers, achieving scalability with traffic, backup configuration and performance optimization with increasing load. With RDS, all these will be managed by AWS.

 

Log handling

Keep all the important logs like Application logs, Syslogs, SSH log etc in EBS volume. You can either schedule regular snapshots of these EBS volume to S3 or you can even sync these log files to an S3 bucket periodically using tools like s3sync.

 

Configuration Management

If you have more than one server or are planning to scale up in future or would like to automate a lot of administration / coding stuffs, you should definitely use one of the Open Source freely available Configuration Management tools like Chef / puppet / Cfengine

Chef is new and has default support for AWS / EC2. We use Chef extensively for managing our infrastructure in AWS. Chef provide a lot of readily available cookbooks ( recipes / roles ) for LAMP, JAVA app, Cassandra, Hadoop, Nagios etc which can be used readily ( or with minimum customization ) to automate the infrastructure setup and configuration. Chef also comes with a tool called Chef-deploy for automating deployment of code.

So using Chef along with tools like Hudson / Cruisecontrol, you can automate the entire setup from infrastructure setup to configuration management to building, deployment and testing of your application.

 

Performance

To improve performance you can implement the following:

(i)Use caching mechanisms like Memcache(DB scaling) / aiCache / Varnish.

(ii)CDN ( Content Delivery Network ) is a must if you want to provide better end-user response time. There are lot of CDN providers but we recommend AWS CloudFront or Akamai for serving static files and images. For start-up and small business, CDN might be costly but as your target audience grows larger and becomes more global, a CDN is necessary to achieve fast response times.

 

Monitoring & Alert

For monitoring, go for open source monitoring tools along with a SaaS based monitoring application.

(i)There are lot of free and open source option available in the market – Nagios, Zenoss,Zabbix etc. This can be automated with Chef in such a way that when a new server is launched in to the cluster, it will be automatically added to the Nagios list of monitored servers.

(ii)You can also use excellent SaaS based monitoring apps like Pingdom, mon.itor.us, site24x7.com etc for monitoring and alerting via email, SMS or Twitter.

(iii)Custom scripts or tools like Munin & Monit for monitoring and restarting services if it crashes.

 

Backup

You can keep copies of code in an S3 Bucket and sync it with tools like s3sync with every update. For DB Backup, in addition to automated RDS Backup, you can take periodical standard DB backups using mysqldump and store it in S3 bucket.You can also use EBS volumes for keeping replica of code and DB Backup with periodical snapshots to S3.

An important thing to note about S3 storage is it is only a Highly available Storage System. It is not backed up automatically. That means if you delete anything manually from s3, it will be forever gone unless you have manually backed it up with multiple copies in S3. So make sure that you have enough backups available in S3.

Amazon S3 organizer FF plugin error NS_ERRR_FILE_ACCESS_DENIED

Today I encountered an error  NS_ERRR_FILE_ACCESS_DENIED after installing Amazon S3 organizer in Firefox. It took me a while to figure out the exact problem and thought I will post it here. The fix is to give write permissions to the folders. Under UNIXes chmod 755 (ie, assigning read and write access will do the trick)

hope this two cents helps someone 🙂