GitHub user tew-axiom added a comment to the discussion: Proposal: support
Master-Slave architecture among components
# Some initial ideas for a "Gorm + DB" solution
## Lease Design
Based on the following considerations:
- Need to ensure only one lease record exists per component
- Define lease expiration conditions
We need a table with roughly the following structure:
```sql
CREATE TABLE component_lease (
-- Primary key: component name (e.g., "discovery", "engine")
component_name VARCHAR(64) PRIMARY KEY,
-- Current holder identifier (pod_name or hostname+pid)
holder_id VARCHAR(128) NOT NULL,
-- Lease acquisition time (millisecond timestamp)
lease_time BIGINT NOT NULL,
-- Last renewal time (millisecond timestamp)
renew_time BIGINT NOT NULL,
-- Optimistic lock version number
version INT NOT NULL DEFAULT 0,
-- Lease TTL (seconds)
ttl INT NOT NULL DEFAULT 30,
);
```
Now we can perform leader election through the following approaches or
strategies, as illustrated:
<img width="320" height="638" alt="截屏2026-01-13 20 48 59"
src="https://github.com/user-attachments/assets/6e1c037e-fc0b-4aa6-a713-94a68c42d17b";
/>
1. **Initial Competition** - Attempt to INSERT lease record
- Success → Become Leader
- Failure (unique key conflict) → Proceed to next step
2. **Seize Expired Lease** - UPDATE WHERE expiration condition
For example:
```sql
... WHERE component_name = 'discovery' AND renew_time < (NOW() - ttl * 1000)
```
At this point, we can determine the current node's role based on the
following feedback:
- RowsAffected > 0 → Become Leader
- RowsAffected = 0 → Become Follower
3. **Periodic Heartbeat**
- **Leader**: Renew every TTL/3 interval (e.g., if TTL=30s, renew every 10s)
- **Follower**: Attempt to compete every TTL/3 interval
4. **Loss of Leadership**
- Renewal failure (database exception/lease preemption) → Stop business
logic → Transition to Follower
## Other Details
- If the database is master-slave, how to ensure lease operates normally? Force
routing to master? How to handle master failure? ProxySQL?
- Lease lifecycle management itself, and integration with existing component
lifecycle
- Edge cases:
- Boundary handling when multiple nodes start simultaneously
- Use database timestamps instead of server/application time to avoid clock
skew
GitHub link:
https://github.com/apache/dubbo-admin/discussions/1380#discussioncomment-15485594
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