PaaS like Amazon Elastic Beanstalk (EB) in some way makes deployment easier.
However it is not always working smoothly.
This afternoon, when I performed "eb deploy", for some reason the new version was not deployed successfully. The deploy process took really long time, and in the end it failed.
I did have experience with this, normally what I do is just terminate the actual EC2 instance associated with EB. If the minimum healthy instances is smaller than the number specified in EB environment configuration, then EB will create new instance. This approach will work however if your minimum instance is 1, it will cause downtime.
To avoid downtime, we can increase minimum instances to 2, which will force EB to create new instance. After a new EC2 instance is created, we can change the minimum back to 1, and then delete the EC2 instance which has issue.