Flow and ClusterFlow
Flows route the selected log messages to the specified outputs. Depending on which log forwarder you use, you can use different filters and outputs, and have to configure different custom resources.
Fluentd flows
Flow
defines a logging flow for Fluentd with filters and outputs.
The Flow is a namespaced
resource, so only logs from the same namespaces are collected. You can specify match
statements to select or exclude logs according to Kubernetes labels
, container and host names. (Match statements are evaluated in the order they are defined and processed only until the first matching select
or exclude
rule applies.) For detailed examples on using the match statement, see log routing.
You can define one or more filters
within a Flow. Filters can perform various actions on the logs, for example, add additional data, transform the logs, or parse values from the records.
The filters in the flow are applied in the order in the definition. You can find the list of supported filters here.
At the end of the Flow, you can attach one or more outputs, which may also be Output
or ClusterOutput
resources.
Flow
resources arenamespaced
, theselector
only selectPod
logs within namespace.ClusterFlow
defines a Flow without namespace restrictions. It is also only effective in thecontrolNamespace
.ClusterFlow
selects logs from ALL namespace.
The following example transforms the log messages from the default
namespace and sends them to an S3 output.
Note: In a multi-cluster setup you cannot easily determine which cluster the logs come from. You can append your own labels to each log using the record modifier filter.
- For the details of
Flow
custom resource, see FlowSpec. - For the details of
ClusterFlow
custom resource, see ClusterFlow. - For details on selecting messages, see Routing your logs with Fluentd match directives
- See the list of supported filters.
syslog-ng flows
SyslogNGFlow
defines a logging flow for syslog-ng with filters and outputs.
syslog-ng is supported only in Logging operator 4.0 or newer.
The Flow is a namespaced
resource, so only logs from the same namespaces are collected. You can specify match
statements to select or exclude logs according to Kubernetes labels
, container and host names. For detailed examples on using the match statement, see log routing with syslog-ng.
You can define one or more filters within a Flow. Filters can perform various actions on the logs, for example, add additional data, transform the logs, or parse values from the records. The filters in the flow are applied in the order in the definition. You can find the list of supported filters here.
At the end of the Flow, you can attach one or more outputs, which may also be Output
or ClusterOutput
resources.
SyslogNGFlow
resources arenamespaced
, theselector
only selectsPod
logs within the namespace.SyslogNGClusterFlow
defines a SyslogNGFlow without namespace restrictions. It is also only effective in thecontrolNamespace
.SyslogNGClusterFlow
selects logs from ALL namespaces.
The following example selects only messages sent by the log-generator application and forwards them to a syslog output.
- For the details of the
SyslogNGFlow
custom resource, see SyslogNGFlowSpec. - For the details of the
SyslogNGClusterFlow
custom resource, see SyslogNGClusterFlow. - For details on selecting messages, see Routing your logs with syslog-ng
- See the list of supported filters.