Error with OpenOB 4.0.2 and Raspbian Stretch Lite about openob

[JamesHarrison]

This looks like a network connection issue, not an issue with the new version - those errors are saying that the server (192.168.1.109) running redis is refusing to talk with you, which usually means you've not set redis to listen on all interfaces or aren't running redis.

[LyonelB]

Redis seems to work:
● redis-server.service - Advanced key-value store
Loaded: loaded (/lib/systemd/system/redis-server.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2018-08-20 15:42:59 UTC; 18h ago
Docs: http://redis.io/documentation,
man:redis-server(1)
Process: 531 ExecStartPost=/bin/run-parts --verbose /etc/redis/redis-server.post-up.d (code=exited, status=0/SUCC
Process: 488 ExecStart=/usr/bin/redis-server /etc/redis/redis.conf (code=exited, status=0/SUCCESS)
Process: 470 ExecStartPre=/bin/run-parts --verbose /etc/redis/redis-server.pre-up.d (code=exited, status=0/SUCCES
Main PID: 530 (redis-server)
CGroup: /system.slice/redis-server.service
└─530 /usr/bin/redis-server 0.0.0.0:6379

Aug 20 15:42:58 raspberrypi systemd[1]: Starting Advanced key-value store...
Aug 20 15:42:59 raspberrypi run-parts[470]: run-parts: executing /etc/redis/redis-server.pre-up.d/00_example
Aug 20 15:42:59 raspberrypi run-parts[531]: run-parts: executing /etc/redis/redis-server.post-up.d/00_example
Aug 20 15:42:59 raspberrypi systemd[1]: Started Advanced key-value store.

---

pi@raspberrypi:~ $ redis-server
754:C 21 Aug 10:28:49.311 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
754:M 21 Aug 10:28:49.319 * Increased maximum number of open files to 10032 (it was originally set to 1024).
754:M 21 Aug 10:28:49.320 # Creating Server TCP listening socket *:6379: bind: Address already in use

[JamesHarrison]

Sure, but is it listening externally? What does ss -napl | grep redis see? Can you post your redis config?

[JamesHarrison]

Looking at this in a bit more detail - if you're using 4.0 you may find protected-mode yes in your config ifle. This appears to be a new security feature Redis has introduced. If you set protected-mode no this should fix it immediately; really though we should look to support authenticated connections for Redis which is a better fix...

[LyonelB]

What does ss -napl | grep redis see?

pi@raspberrypi:~ $ ss -napl | grep redis
pi@raspberrypi:~ $

Can you post your redis config?

bind 0.0.0.0
protected-mode no (after change it)
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize yes
supervised no
pidfile /var/run/redis/redis-server.pid
loglevel notice
logfile /var/log/redis/redis-server.log
databases 16
save 900 1
save 300 10
save 60 10000
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename dump.rdb
dir /var/lib/redis
slave-serve-stale-data yes
slave-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-disable-tcp-nodelay no
slave-priority 100
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
lua-time-limit 5000
slowlog-max-len 128
latency-monitor-threshold 0
notify-keyspace-events ""
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
list-max-ziplist-size -2
list-compress-depth 0
set-max-intset-entries 512
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
aof-rewrite-incremental-fsync yes

protected-mode no

I do it and restart redis-server but i still have the error and OpenOB don't work

[jonty-comp]

Another helpful test would be to run redis-cli -h 192.168.1.109 -p 6379 from your openob client, and see if that can connect.

[LyonelB]

192.168.1.109 → recepter
192.168.1.161 → emetter

On the recepter (192.168.1.109)
pi@raspberrypi:~ $ redis-cli -h 192.168.1.109 -p 6379
Could not connect to Redis at 192.168.1.109:6379: Connection refused
Could not connect to Redis at 192.168.1.109:6379: Connection refused
not connected>

[JamesHarrison]

OK, that's very certainly not an OpenOB issue then - if redis can't talk to redis, it's probably redis or a firewall! Does your machine have a firewall, is port 6379 open?

[LyonelB]

Both raspberry are plugged into the same network switch. I do not understand why it worked by installing with:
sudo pip install git + https://github.com/jonty-comp/[email protected]

and that it does not work with OpenOB 4.0

[JamesHarrison]

OK - if you can't connect to redis from the client then OpenOB certainly won't work, regardless of branch. If you can get to the point where that redis-cli command succeeds but OpenOB doesn't, then further investigation will be needed.

[LyonelB]

"bind: Address already in use" → Is it ok ?

pi@raspberrypi:~ $ redis-server
920:C 22 Aug 10:14:15.293 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
920:M 22 Aug 10:14:15.301 * Increased maximum number of open files to 10032 (it was originally set to 1024).
920:M 22 Aug 10:14:15.302 # Creating Server TCP listening socket *:6379: bind: Address already in use

[JamesHarrison]

That suggests there's already something using port 6379 - probably your OS running redis-server through systemd.

[LyonelB]

must redis-server be installed only on the receiving machine?

[JamesHarrison]

It can be installed on either, but must be present on and running on at least one, and both clients pointed at that server.
I'm going to close this, as it's not a bug/code issue but a redis/config issue - the mailing list is a better place to discuss.

[LyonelB]

I do not know why but since last night everything works!
I updated the tutorial on the site technic2radio.fr: https://technic2radio.fr/openob-liaison-ip-par-raspberry-pi/