As you scale up your project, the default logging environment might need some
adjustments.
For example, if you are missing logs, you might have to increase the rate limits for journald.
You can adjust the number of messages to retain for a specified period of time to ensure that
cluster logging does not use excessive resources without dropping logs.
You can also determine if you want the logs compressed, how long to retain logs, how or if the logs are stored,
and other settings.
Procedure
-
Create a journald.conf
file with the required settings:
Compress=yes (1)
ForwardToConsole=no (2)
ForwardToSyslog=no
MaxRetentionSec=1month (3)
RateLimitBurst=10000 (4)
RateLimitIntervalSec=30s
Storage=persistent (5)
SyncIntervalSec=1s (6)
SystemMaxUse=8g (7)
SystemKeepFree=20% (8)
SystemMaxFileSize=10M (9)
1 |
Specify whether you want logs compressed before they are written to the file system.
Specify yes to compress the message or no to not compress. The default is yes . |
2 |
Configure whether to forward log messages. Defaults to no for each. Specify:
-
ForwardToConsole to forward logs to the system console.
-
ForwardToKsmg to forward logs to the kernel log buffer.
-
ForwardToSyslog to forward to a syslog daemon.
-
ForwardToWall to forward messages as wall messages to all logged-in users.
|
3 |
Specify the maximum time to store journal entries. Enter a number to specify seconds. Or
include a unit: "year", "month", "week", "day", "h" or "m". Enter 0 to disable. The default is 1month . |
4 |
Configure rate limiting. If, during the time interval defined by RateLimitIntervalSec , more logs than specified in RateLimitBurst
are received, all further messages within the interval are dropped until the interval is over. It is recommended to set
RateLimitIntervalSec=30s and RateLimitBurst=10000 , which are the defaults. |
5 |
Specify how logs are stored. The default is persistent :
-
volatile to store logs in memory in /var/log/journal/ .
-
persistent to store logs to disk in /var/log/journal/ . systemd creates the directory if it does not exist.
-
auto to store logs in in /var/log/journal/ if the directory exists. If it does not exist, systemd temporarily stores logs in /run/systemd/journal .
-
none to not store logs. systemd drops all logs.
|
6 |
Specify the timeout before synchronizing journal files to disk for ERR, WARNING, NOTICE, INFO, and DEBUG logs.
systemd immediately syncs after receiving a CRIT, ALERT, or EMERG log. The default is 1s . |
7 |
Specify the maximum size the journal can use. The default is 8g . |
8 |
Specify how much disk space systemd must leave free. The default is 20% . |
9 |
Specify the maximum size for individual journal files stored persistently in /var/log/journal . The default is 10M .
|
If you are removing the rate limit, you might see increased CPU utilization on the
system logging daemons as it processes any messages that would have previously
been throttled.
|
|
-
Convert the journal.conf
file to base64:
$ export jrnl_cnf=$( cat /journald.conf | base64 -w0 )
-
Create a new MachineConfig
object for master or worker and add the journal.conf
parameters:
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
labels:
machineconfiguration.openshift.io/role: worker
name: 50-corp-journald
spec:
config:
ignition:
version: 3.1.0
storage:
files:
- contents:
source: data:text/plain;charset=utf-8;base64,${jrnl_cnf}
mode: 0644 (1)
overwrite: true
path: /etc/systemd/journald.conf (2)
1 |
Set the permissions for the journal.conf file. It is recommended to set 0644 permissions. |
2 |
Specify the path to the base64-encoded journal.conf file. |
-
Create the machine config:
$ oc apply -f <filename>.yaml
The controller detects the new MachineConfig
object and generates a new rendered-worker-<hash>
version.
-
Monitor the status of the rollout of the new rendered configuration to each node:
$ oc describe machineconfigpool/worker
Example output
Name: worker
Namespace:
Labels: machineconfiguration.openshift.io/mco-built-in=
Annotations: <none>
API Version: machineconfiguration.openshift.io/v1
Kind: MachineConfigPool
...
Conditions:
Message:
Reason: All nodes are updating to rendered-worker-913514517bcea7c93bd446f4830bc64e