I've been wanting to compile a checklist of basic precautions that could be useful to Internet startups (especially those in the SaaS space)
ever since the MongoHQ/Buffer security incident.
As evident by that incident, a security breach at a SaaS provider could have catastrophic ripple effects - your customer's customers data could be compromised!
Redis is a popular key-value store that is fast, reliable and simple to administer.
While Redis asynchronous master-slave replication is well known,
Sentinel seems to be a little known feature.
Sentinel is a built-in feature in v2.6+ that provides an automatic failover mechanism,
i.e. promotion of a slave to replace a failing master, reconfiguring other slaves to use a new master and
informing client applications about the new address to use when connecting to a master.
Foreman is an intra-app process manager used in a development environment.
Although its main use case is that, I've started to use it to manage inter-app dependencies as well.
I first started working with Opscode Chef in early 2011 while on a consulting project
(native environments' support was still a beta feature back then).
Since late 2012, I've been working extensively with Chef once again for Bitium.