Ec2

I’ve often found myself with an instance id that I want to login to look at something. It sucks looking up the IP when you don’t know the DNS name. I’m sure there are other ways to do this but here is what I came up with. getec2ip() { aws ec2 describe-instances --instance-ids $1 | jq [.Reservations[0].Instances[0].PrivateIpAddress] | jq --raw-output .[] } assh() { host=$(getec2ip ${1}) ssh user@${host} } This relies on the aws cli and jq to parse out the ip and has made it much easier for me to quickly hop on an instance. ...

While troubleshooting site to site links running OpenVPN recently I ran into an issue with MTU sizing on the ec2 end. When we originally setup the links we followed the performance tuning advice found here. The relevant portion is that we set tun-mtu 6000 Why did we do this? Here’s OpenVPN’s explanation By increasing the MTU size of the tun adapter and by disabling OpenVPN's internal fragmentation routines the throughput can be increased quite dramatically. The reason behind this is that by feeding larger packets to the OpenSSL encryption and decryption routines the performance will go up. The second advantage of not internally fragmenting packets is that this is left to the operating system and to the kernel network device drivers. For a LAN-based setup this can work, but when handling various types of remote users (road warriors, cable modem users, etc) this is not always a possibility. During later testing we discovered that we could easily push 40mb/s over the OpenVPN tunnel into the ec2 instance, but only 1mb/s or less going the opposite direction. Obviously not ideal. ...