Create Rsyslog Service in Kubernetes

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One of the biggest benefit of Kubernetes is that you can build some once difficult infra services quickly, and disposable for testing purpose. Let’s create a rsyslog service on OpenShift.

Create Rsyslog Container Image

Create the following Dockerfile,

FROM ubuntu
RUN apt-get update && apt-get install -y rsyslog && mkdir -p /logs
COPY rsyslog.conf /rsyslog.conf
ENTRYPOINT ["rsyslogd", "-n", "-f", "/rsyslog.conf"]

We run the rsyslog with the “-n” option to let it run foreground as a normal process. The “-f” option supply the configuration file, which is shown as below,

module (load="imudp" )
input (type="imudp" port="514")
module (load="imtcp")
input (type="imtcp" port="514")

template (
  name="LogsByDate"
  type="string"
  string="/logs/%$YEAR%-%$Month%-%$Day%.log"
)

action(type="omfile" dynaFile="LogsByDate")

The first 4 lines load the TCP and UDP module. Our syslog service will listen on both UDP/514 and TCP/514. We then create a string template which will be the log file name based on current date. Finally we will recieve the log entries and write it into the log file created dynamically based on the date. The omfile type is the module for the output file.