Amazon EC2

Amazon's Cloud provides a flexible platform to deploy Eden scalably.

The costs aren't fixed & can be difficult to predict, despite their ​calculator, but are competitive, especially in Singapore, which is a good base for the Asia Pacific region. Users who are using the free tier: Remember - after 750 hours, your trial will end and the credit card on file will be charged based on the rates shown in EC2. You can prevent these charges by closing the AWS account from the ​AWS account management page.

1. Create AWS Account

If you haven't already, create an Amazon AWS account through ​their site.

2. Create Instance

1: Log in to the Management Console

• ​https://console.aws.amazon.com

2: Select a Region

Amazon supports multiple Regions in order to provide a service closest to your users.

• Namespaces of Instances, Volumes & Snapshots are unique only within a Region.
• Within each Region, there are a couple of Availability Zones to allow spreading the risk across different facilities.
• Volumes are located within a specific Availability Zone
• Bandwidth transfers are free within an Availability Zone

3: Launch Instance

This is a blue button in the EC2 Dashboard

4: Choose an Amazon Machine Image (AMI)

• Recommend using the AWS Marketplace and selecting the Debian GNU/Linux 9 (Stretch) image
• alternatively it is possible to use Community AMIs, use latest debian-stretch-amd64-hvm image, which supports the new T2.micro free tier instances
• In time we may provide pre-built "Sahana Eden" AMIs (some old unmaintained ones may be available in some regions)

5: Choose an Instance Type

• ​https://aws.amazon.com/ec2/instance-types/
• The free starter 'T2.micro' instance is flexible as it can run both 32-bit & 64-bit Operating Systems....it is suitable for prototyping, development, QA and smaller scale production services. Note that for User Training it can be good to increase capacity as this typically has more users accessing the system concurrently than in normal operations.
• For production-level performance of larger deployments, we recommend a balance of processor & RAM, so the M5.large would be our current recommendation, usually purchased as a 1 year reservation

6: Configure Instance Details

Default settings are fine, except you should open the 'Advanced Details' at the bottom & paste the contents of the user-data.sh file into the User Data section:

• ​https://raw.githubusercontent.com/sahana/eden_deploy/master/user-data.sh

If you leave this unedited then this will install a Setup tool which will allow you to configure your Sahana Eden instance through a GUI

if you wish to bypass the GUI then you can delete the last 2 lines & edit the last line to select the template that you wish to run, to set your site's Public DNS, and the email address used to send mails From:

bash bootstrap.sh mytemplate myhostname.mydomain sender@domain

7: Add Storage, Add Tags

Default settings are fine.

8: Configure Security Group

'Select existing' to avoid the confusion caused by having multiple groups.

9: Create KeyPair

Ensure that you keep the generated private key safe...save as private.pem. You will need this file to log into your instance.

10: Configure Security Group

NETWORK & SECURITY > Security Groups

You will need to set the following Inbound Rules:

• HTTP | TCP | 80
• HTTPS | TCP | 443
• SSH | TCP | 22

Restricting the source will add further security, but obviously also restricts your ability to administer

11: Associate Elastic IP

Each time you start an instance up, it will be assigned a new IP ('Public DNS') although this can be overcome using an Elastic IP:

1. NETWORK & SECURITY > Elastic IPs
2. Allocate New Address
3. Associate Address. Set the instance to your new instance

Remember to set up Reverse DNS for your Elastic IP to be able to send emails reliably:

• ​https://aws-portal.amazon.com/gp/aws/html-forms-controller/contactus/ec2-email-limit-rdns-request

NB If you have a free EC2 instance, be sure to release your Elastic IP if you shut down your instance. IPv4 addresses are a "scarce resource" so Amazon will charge you for wasting one if you keep it assigned to your instance while you are not using it.

12: Gain SSH access

In order to get the public key (needed by SecureCRT for instance) then you need to login using CLI & retrieve it (username 'admin' for the AWS MarketPlace Debian, username 'root' for some other Images):

ssh -l admin -i private.pem <hostname>
cat ~/.ssh/authorized_keys

On Windows, you can use Cygwin to get a CLI SSH client.

SecureCRT needs the private key storing as <filename> & the public as <filename.pub> (all on one line)

Recovering From a Lost Keypair

If you lose your keypair then you need to:

• Create a new keypair in the AWS console & download the generated private key
• Stop the instance
• Create an AMI from this instance
• Wait for the AMI to be ready
• Launch a new instance using this AMI
• Re-associate the Public IP
• Delete the old instance
• Deregister the AMI
• Delete the snapshot used to create the AMI

Thanks to: ​http://itkbcentral.blogspot.co.uk/2011/07/replace-lost-key-pair-existing-aws-ec2.html

3. Install & Configure Sahana

This should happen automatically through the user-data.sh script that you used earlier. You can check the progress of this using:

tail -f -n 45 /var/log/user-data.log

If you are not using the user-data.sh then you can use the older Manual scripts

See Admin Guide - especially read how to set the sender & approver emails

Optional Instance Adjustments

Add Swap partition

You can add a swap partition in order to improve performance further:

• Create Volume in AWS Console (e.g. 4Gb)
• Attach as /dev/sdf

  sudo su -
  swapoff -a
  mkswap /dev/xvdf
  swapon -a
  # Make persistent across reboots
  cat << EOF >> "/etc/fstab"
  /dev/xvdf swap  swap    defaults 0 0
  EOF
  rm -f /mnt/swapfile
  
  

Add Storage

If you need an additional disk for Storage then configure a new volume in the AWS console. There are several different types available: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html For the database (normally on the boot volume) you want at least a General Purpose SSD (gp2). For additional storage (Prepop, Logs, Uploads, etc) then a Cold HDD (sc1) provides a cheaper per-Gb option, but needs a minimum of 500Gb provisioned.

Attach as /dev/sdf, then in Linux console:

sudo su -
fdisk /dev/xvdf
n
(accept defaults)
w
mkfs.ext4 /dev/xvdf
tune2fs -m 0 /dev/xvdf # Remove 5% reservation for reserved blocks
mkdir /data
cat << EOF >> "/etc/fstab"
/dev/xvdf /data ext4    defaults,barrier=0 1 1
EOF
mount /data

Disk Striping

For DB I/O performance increase can stripe multiple EBS

• monitoring data is available to see if this is the issue

CLI Tools

You can do this using the AWS EC2 Console or else you can do it via the CLI To use any of the AWS CLI tools on your own machine to remotely manage instances, then you need to generate a unique X.509 Certificate per account. This can be done from the 'Security Credentials' page within your account.

CLI Management

There are extensive CLI tools available to manipulate your instances.

• Java CLI for Windows/Linux
  • ​http://aws.amazon.com/developertools/351
  • ​http://serktools.com/2009/05/19/setting-up-ec2-command-line-tools-on-windows/
  • ​http://docs.amazonwebservices.com/AWSEC2/latest/CommandLineReference/
• Python: ​http://libcloud.apache.org

CLI Script

Edit the settings as-indicated as you proceed through the script

# Settings for Instance
set EC2_URL=https://ec2.us-east-1.amazonaws.com
set ZONE=us-east-1c
set DEV=i-950895f1
set OLD=vol-31f5a35d
# Stop Host
ec2stop %DEV%
# Create a snapshot
ec2-create-snapshot %OLD%
# Record the snapshot ID
set SNAPSHOT=snap-63f89d08
# Create new volume from snapshot
ec2-create-volume -z %ZONE% --size 4 --snapshot %SNAPSHOT%
# Record the new Volume ID
set NEW=vol-a9c2a3c4
# Attach new volume as secondary
ec2-attach-volume -i %DEV% %NEW% -d /dev/sdb1
# Delete Snapshot (if no data in yet)
ec2-delete-snapshot %SNAPSHOT%
# Start Host
ec2start %DEV%
# Re-attach the Public IP
# Login
mkdir /mnt/data
echo '/dev/xvdb1 /mnt/data ext3 defaults,noatime 0 0' >> /etc/fstab
mount /mnt/data
resize2fs /dev/xvdb1
umount /mnt/data
shutdown -h now
# Unattach volumes
ec2-detach-volume -i %DEV% %OLD%
ec2-detach-volume -i %DEV% %NEW%
# Attach volume as boot
ec2-attach-volume -i %DEV% %NEW% -d /dev/sda1
# Attach old volume for /var/log
ec2-attach-volume -i %DEV% %OLD% -d /dev/sdb1
# OR Delete old volume
#ec2-delete-volume %OLD%
# Start Host
ec2start %DEV%
# Re-attach the Public IP
# Login
df -h
# Use the old partition for /var/log (to avoid DoS)
vi /etc/fstab
/dev/xvdb1 /var/log  ext3    noatime 0 0

mv /var/log /var/log_old
mkdir /var/log
mount /var/log
mv /var/log_old/* /var/log
rm -rf /var/log/bin/
rm -rf /var/log/boot/
rm -rf /var/log/dev/
rm -rf /var/log/etc/
rm -rf /var/log/home/
rm -rf /var/log/initrd.img
rm -rf /var/log/lib/
rm -rf /var/log/mnt/
rm -rf /var/log/media/
rm -rf /var/log/opt/
rm -rf /var/log/proc/
rm -rf /var/log/root/
rm -rf /var/log/sbin/
rm -rf /var/log/selinux/
rm -rf /var/log/srv/
rm -rf /var/log/tmp/
rm -rf /var/log/usr/
rm -rf /var/log/var/
rm -rf /var/log/vmlinuz
rm -rf /var/log_old

Building AMIs for easier deployment

See: InstallationGuidelines/Amazon/AMI

Troubleshooting

To troubleshoot any errors in installation of EC2 visit its ​documentation. If you encounter problems installing eden on the EC2 instance, you can contact us via IRC or the mailing list.