I forwarded the log to graylog, but within a few hours, fluent-bit stopped sending the data. When I restarted fluent-bit, the log was sent back to normal

I forwarded the log to graylog, but within a few hours, fluent-bit
stopped sending the data. When I restarted fluent-bit, the log was
sent back to normal.
Error which we faces:- [net] TCP connection failed: 12201 (Connection refused) [error] [output:gelf:gelf.0] no upstream connections available

apiVersion: v1
kind: ConfigMap
metadata:
name: fluent-bit-config
namespace: logging
labels:
k8s-app: fluent-bit
data:

Configuration files: server, input, filters and output

======================================================

fluent-bit.conf: |
[SERVICE]
Flush 1
Log_Level info
Daemon off
Parsers_File parsers.conf
HTTP_Server On
HTTP_Listen 0.0.0.0
HTTP_Port 2020

@INCLUDE input-kubernetes.conf
@INCLUDE filter-kubernetes.conf
@INCLUDE output-graylog.conf

input-kubernetes.conf: |
[INPUT]
Name tail
Tag kube.*
Path /var/log/containers/*.log
Parser docker
DB /var/log/flb_kube.db
Mem_Buf_Limit 5MB
Skip_Long_Lines On
Refresh_Interval 10

filter-kubernetes.conf: |
[FILTER]
Name kubernetes
Match kube.*
Kube_URL https://kubernetes.default.svc:443
Kube_CA_File /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
Kube_Token_File /var/run/secrets/kubernetes.io/serviceaccount/token
Kube_Tag_Prefix kube.var.log.containers.
Merge_Log On
Merge_Log_Key log_processed
K8S-Logging.Parser On
K8S-Logging.Exclude Off

output-graylog.conf: |
[OUTPUT]
Name gelf
Match *
Host ${FLUENT_GRAYLOG_HOST}
Port ${FLUENT_GRAYLOG_PORT}
Mode tcp
Gelf_Short_Message_Key log

parsers.conf: |
[PARSER]
Name json
Format json
Time_Key time
Time_Format %d/%b/%Y:%H:%M:%S %z

[PARSER]
    Name        docker
    Format      json
    Time_Key    time
    Time_Format %Y-%m-%dT%H:%M:%S.%L
    Time_Keep   On

[PARSER]
    Name        syslog
    Format      regex
    Regex       ^\<(?<pri>[0-9]+)\>(?<time>[^ ]* {1,2}[^ ]* [^ ]*) (?<host>[^ ]*) (?<ident>[a-zA-Z0-9_\/\.\-]*)(?:\[(?<pid>[0-9]+)\])?(?:[^\:]*\:)? *(?<message>.*)$
    Time_Key    time
    Time_Format %b %d %H:%M:%S

If you are lucky you might get a Graylog Community member who knows fluent-bit and might be able to help (I don’t) Your qestion seems that it would be better served in the fluent-bit community

thnks for the response…ok i will join fluent bit community also…

but meanwhile if any idea on this then please let me know…