Migrating from etcd to tega

[araobp]

I would prefer tega rather than etcd:

• tega is schema-less
• tega supports JSON types, etcd supports string-type only
• tega can accept CRUD operation at an arbitrary path/depth
• tega supports Data Change Notification (DCN) at an arbitrary path/depth
• tega supports pubsub and bi-directional communications: I don't need to know IP addresses of each docker containers
• tega supports RPC inventory: you can invoke RPC APIs from tega CLI
• tega can run on Raspberry Pi: small footprint
• tega supports rollback: MUST for router configuration
• tega supports two-phase commit: MUST for router configuration
• tega supports an interactive CLI, etcd does not
• I don't need a RAFT-based data base for such a small project
• tega supports a plugin framework
• tega uses coroutine (tornado), zero-overhead and good for a single-core CPU

I need to develop tega driver for golang.

On the other hand, nlan agent (golang) seems to run faster than the original neutron-lan agent (python):

• Golang supports light-weight thread (goroutine)
• Python has an overhead (a few M bytes) of its runtime: python interpreter: no good for docker/RaspberryPi
• Python (CPython) is not good at parallel computing because of GIL

BTY, I would use ZooKeeper rather than etcd, since ZooKeeper supports "ephemeral nodes" that are useful features for SDN-related projects. But for this project, I have decided to use tega, because I need to run a config DB on my small Raspberry Pi!

[araobp]

etcd consumes 2% CPU resource / 4% of memory of my Raspberry Pi, whereas tega consumes 0% CPU (co-routine/non-blocking IO based) and 3% of memory.

tega runs much lighter than etcd.

On my old 32 bit PC, etcd makes go compile much slower. I don't know the reason why. tega does not affect anything.

Co-routine-based database is good for my small project with a very old PC and Raspberry Pi

[araobp]

• MD-SAL for sharing topology/flow info among software components in a multi-vendor environment: optical transport (DWDM/OTN) vendors use OpenDaylight just for inter-operability with other vendors
• MP-BGP for sharing IP/mac addresses between routers and also between controllers: traditional routers and edge-overlay-based SDN controller such as OpenContrail.
• ZooKeeper and Cassandra for a very large-scale network management: OpenContrail and midonet.
• etcd for Docker/Kubernetes
• tega for my small project

[araobp]

I have just implemented a sample of tega driver for golang: https://github.com/araobp/tega/blob/master/driver/driver.go

Using tega is much easier to use than using etcd, because tega supports JSON types:

• https://github.com/araobp/nlan/blob/master/db/tega.go
• https://github.com/araobp/nlan/blob/master/util/etcd.go

[araobp]

Migration completed.