diff options
Diffstat (limited to 'qpid/cpp/design_docs/new-cluster-design.txt')
| -rw-r--r-- | qpid/cpp/design_docs/new-cluster-design.txt | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/qpid/cpp/design_docs/new-cluster-design.txt b/qpid/cpp/design_docs/new-cluster-design.txt index f2063524de..a162ea68ec 100644 --- a/qpid/cpp/design_docs/new-cluster-design.txt +++ b/qpid/cpp/design_docs/new-cluster-design.txt @@ -234,10 +234,10 @@ Note: - Updatee stalls clients until the update completes. (Note: May be possible to avoid updatee stall as well, needs thought) -** Cluster API +** Internal cluster interface -The new cluster API is similar to the MessageStore interface, but -provides more detail (message positions) qand some additional call +The new cluster interface is similar to the MessageStore interface, but +provides more detail (message positions) and some additional call points (e.g. acquire) The cluster interface captures these events: @@ -284,13 +284,33 @@ cluster uses the same messagea allocation threading/logic as a standalone broker, with a little extra asynchronous book-keeping. If a queue has multiple consumers connected to multiple brokers, the -new cluster time shares the queue which is less efficient than having -all consumers connected to the same broker. +new cluster time-shares the queue which is less efficient than having +all consumers on a queue connected to the same broker. ** Flow control New design does not queue up CPG delivered messages, they are processed immediately in the CPG deliver thread. This means that CPG's - flow control is sufficient for qpid. +flow control is sufficient for qpid. + +** Live upgrades + +Live upgrades refers to the ability to upgrade a cluster while it is +running, with no downtime. Each brokers in the cluster is shut down, +and then re-started with a new version of the broker code. + +To achieve this +- Cluster protocl XML file has a new element <version number=N> attached + to each method. This is the version at which the method was added. +- New versions can only add methods, existing methods cannot be changed. +- The cluster handshake for new members includes the protocol version + at each member. +- The cluster's version is the lowest version among its members. +- A newer broker can join and older cluster. When it does, it must restrict + itself to speaking the older version protocol. +- When the cluster version increases (because the lowest version member has left) + the remaining members may move up to the new version. + + * Design debates ** Active/active vs. active passive |