Redis sentinel node can not sync after failover - redis

Question

We have setup Redis with sentinel high availability using 3 nodes. Suppose fist node is master, when we reboot first node, failover happens and second node becomes master, until this point every thing is OK. But when fist node comes back it cannot sync with master and we saw that in its config no "masterauth" is set.
Here is the error log and Generated by CONFIG REWRITE config:
1182:S 29 May 2021 13:49:42.713 * Reconnecting to MASTER 192.168.1.2:6379 after failure
1182:S 29 May 2021 13:49:42.716 * MASTER <-> REPLICA sync started
1182:S 29 May 2021 13:49:42.716 * Non blocking connect for SYNC fired the event.
1182:S 29 May 2021 13:49:42.717 * Master replied to PING, replication can continue...
1182:S 29 May 2021 13:49:42.717 * (Non critical) Master does not understand REPLCONF listening-port: -NOAUTH Authentication required.
1182:S 29 May 2021 13:49:42.717 * (Non critical) Master does not understand REPLCONF capa: -NOAUTH Authentication required.
1182:S 29 May 2021 13:49:42.717 * Partial resynchronization not possible (no cached master)
1182:S 29 May 2021 13:49:42.718 # Unexpected reply to PSYNC from master: -NOAUTH Authentication required.
1182:S 29 May 2021 13:49:42.718 * Retrying with SYNC...
# Generated by CONFIG REWRITE
save 3600 1
save 300 100
save 60 10000
user default on #eb5fbb922a75775721db681c49600c069cf686765eeebaa6e18fad195812140d ~* &* +#all
replicaof 192.168.1.2 6379
What is the problem?
Config Sample:
bind 127.0.0.1 -::1 192.168.1.3
protected-mode yes
port 6379
tcp-backlog 511
timeout 0
tcp-keepalive 300
daemonize yes
supervised systemd
pidfile "/var/run/redis_6379.pid"
loglevel notice
logfile ""
databases 16
always-show-logo no
set-proc-title yes
proc-title-template "{title} {listen-addr} {server-mode}"
stop-writes-on-bgsave-error yes
rdbcompression yes
rdbchecksum yes
dbfilename "dump.rdb"
rdb-del-sync-files no
dir "/"
replicaof 192.168.1.2 6379
masterauth "redis"
replica-serve-stale-data yes
replica-read-only yes
repl-diskless-sync no
repl-diskless-sync-delay 5
repl-diskless-load disabled
repl-disable-tcp-nodelay no
replica-priority 100
acllog-max-len 128
requirepass "redis"
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-flush no
lazyfree-lazy-user-del no
lazyfree-lazy-user-flush no
oom-score-adj no
oom-score-adj-values 0 200 800
disable-thp yes
appendonly no
appendfilename "appendonly.aof"
appendfsync everysec
no-appendfsync-on-rewrite no
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
aof-load-truncated yes
aof-use-rdb-preamble yes
lua-time-limit 5000
slowlog-log-slower-than 10000
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
stream-node-max-bytes 4kb
stream-node-max-entries 100
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10
dynamic-hz yes
aof-rewrite-incremental-fsync yes
rdb-save-incremental-fsync yes
jemalloc-bg-thread yes

Answer 1

For those who may run into same problem, problem was REDIS misconfiguration, after third deployment we carefully set parameters and no problem was found.