When you create a ZooKeeper engine in Microservices Engine (MSE), default parameter values are applied. You can modify timing, session timeout, connection, and data parameters to optimize engine performance for your workload.
Prerequisites
Before you begin, make sure that you have:
Parameter reference
Timing parameters
TickTime is the base time unit for ZooKeeper. Other timing parameters are expressed as multiples of TickTime.
| Parameter | Description |
|---|---|
TickTime | Base time unit that regulates heartbeats and timeouts. All tick-based parameters reference this value. |
InitLimit | Maximum time (in ticks) for followers to connect and sync to a leader. The actual timeout equals InitLimit multiplied by TickTime. |
SyncLimit | Maximum time (in ticks) for followers to sync with the leader. Followers that fall too far behind are dropped. |
Session timeout parameters
| Parameter | Description |
|---|---|
SessionTimeout | Client-negotiated session timeout. The server clamps this value to the range defined by MinSessionTimeout and MaxSessionTimeout. |
MinSessionTimeout | Minimum session timeout the server allows a client to negotiate. |
MaxSessionTimeout | Maximum session timeout the server allows a client to negotiate. |
Note: To configure session timeout parameters, upgrade from the open source ZooKeeper version to the MSE ZooKeeper version. For details, see Features of ZooKeeper editions.
Connection and data parameters
| Parameter | Description |
|---|---|
MaxClientCnxns | Maximum number of concurrent client connections per IP address. |
Jute.Maxbuffer | Maximum data size (in bytes) that a single znode can store. |
OpenSuperAcl | Enables super Access Control List (ACL) access for the ZooKeeper engine. |
Modify engine parameters
Log on to the MSE console and select a region in the top navigation bar.
In the left-side navigation pane, choose Microservices Registry > Instances.
On the Instances page, click the name of the instance.
In the left-side navigation pane, click Parameter Settings. Click Edit in the upper-left corner, and then configure the parameters.
Click Save and Restart Instance.
After the instance restarts, return to the Parameter Settings page and verify that the parameter values are updated.
How session timeout negotiation works
When a client connects to a ZooKeeper engine, the server and client negotiate the session timeout. The server enforces the configured bounds:
If the client timeout is less than
MinSessionTimeout, the server overrides it with theMinSessionTimeoutvalue.If the client timeout is greater than
MaxSessionTimeout, the server overrides it with theMaxSessionTimeoutvalue.
The effective timeout range is always [MinSessionTimeout, MaxSessionTimeout].
Example: A ZooKeeper engine has MinSessionTimeout set to 3,000 ms and MaxSessionTimeout set to 5,000 ms. A client requests a session timeout of 1,000 ms (minimum) and 6,000 ms (maximum). After negotiation, the effective minimum session timeout is 3,000 ms and the effective maximum session timeout is 5,000 ms.
Production considerations
Avoid setting
MinSessionTimeoutandMaxSessionTimeoutto very small values. Small values cause clients to detect connection timeouts frequently, which disconnects sessions and can lead to system failures. Use the default values unless your workload requires specific tuning.