why dynomite not check redis status about dynomite

[ipapapa]

If Dynomite cannot send a request to Redis, it will report "ERR storage: connection refused". At the time of Redis disconnection, Dynomite reports it at the log file as well. Moreover, there are some health check stats printed out as a JSON file in port 22222 (you may see them from your browser http://node_ip:22222/info). Did you check them?

[mfouilleul]

"how can known backend redis status by dynomite"

By the command PING no?

Max

Le 25 août 2015 à 17:47, Ioannis Papapanagiotou [email protected] a écrit :

If Dynomite cannot send a request to Redis it should be reported in the log files. Moreover, there are some health check stats printed out as a JSON file in port 22222 (you see them from your browser http://node_ip:22222/info). Did you check them?

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[xichehe]

ping or curl Dynomite node to check backend redis status,before every client set/get key request?

[ipapapa]

Your application should have a failover strategy based on the exception. For example,
GET/SET with Redis down/Dynomite up ---> "(err) ERR Storage: Connection Refused".
GET/SET with Dynomite down ---> "Could not connect to Redis at ip_address:port_number: Connection refused"

[ipapapa]

@xichehe has your issue been answered?

[xichehe]

when GET/SET with Redis down/Dynomite up, my code can't get some exception use phpredis extension~,need some server side config?
if Dynomite up,backend redis is down, why Dynomite route client request to bad redis service,why not Connection Refused?

[ipapapa]

Dynomite returns two different error messages for each case. The reason that Dynomite does not return "connection refused" is because the client is able to establish a connection with Dynomite even if Redis is down. It is up to the client API to capture the error message ("(err) ERR Storage: Connection Refused" or "Connection refused") from Dynomite and throw the proper exception to the application. Most clients return the proper exceptions (e.g. redis-py, redis-cli etc.). phpredis seems to throw a RedisException only if the server is unreachable (overloaded, Dynomite is down, connectivity issues): https://github.com/phpredis/phpredis#class-redisexception
If Dynomite is reachable and Redis is down, phpredis may return FALSE (based on the documentation, I have not tested it).

[xichehe]

thx ipapapa!
I find some strange matter,if Dynomite up and redis down,redis-cli client can set/get some key,but ping cmd will capture the error message:ERR Storage: Connection Refused.

[ipapapa]

This is not the case. For every command that is issued from the client towards Dynomite with Redis down the exception will appear on the cli: ERR Storage: Connection Refused. Did you start redis-cli with the dynomite port: i.e. -p 8102?