Review changes suggested to revise the Metrics related files into a more
logical class structure.
Also fixup grammar typos in docs strings and any trailing metrics that
have been recently added to vmpooler.
This change adds a capability to vmpooler to provision instances on
demand. Without this change vmpooler only supports retrieving machines
from pre-provisioned pools.
Additionally, this change refactors redis interactions to reduce round
trips to redis. Specifically, multi and pipelined redis commands are
added where possible to reduce the number of times we are calling redis.
To support the redis refactor the redis interaction has changed to
leveraging a connection pool. In addition to offering multiple
connections for pool manager to use, the redis interactions in pool
manager are now thread safe.
Ready TTL is now a global parameter that can be set as a default for all
pools. A default of 0 has been removed, because this is an unreasonable
default behavior, which would leave a provisioned instance in the pool
indefinitely.
Pool empty messages have been removed when the pool size is set to 0.
Without this change, when a pool was set to a size of 0 the API and pool
manager would both show that a pool is empty.
Previously a connection pooler class was added. This commit modifies the Dummy
VM Provider to use a connection pooler. While the Dummy provider strictly
speaking does not use connections, this allows testing to see what happens when
connection pools are stressed or exhausted. This commit:
- Modifies functions to use a connection pool object for the public API
functions
- Modifies the VMPooler YAML with new settings for connection pool size and
timeout
Previously the only VM Provider was vSphere however this made testing and making
changes difficult as it required a functioning vSphere instance. This commit
adds a Dummy Provider which presents a VM provider to Pool Manager but manages
provisioned "VM"s in a hashtable. The Dummy Provider can also be configured to
randomly fail operations and take random amounts of time to perform operations,
such as cloning a VM, which is useful to see how the Pool Manager copes with
these events.
This commit also updates the configuration YAML documentation and adds
appropriate unit tests.
