This troubleshooting guide includes step-by-step instructions that should resolve most issues with logs.

Filter logs of same application/service from different host

If you have a application/service which is emitting similar kind of logs but there are multiple instances of it running on different hosts you can identify them by adding a resource attribute.

There are different ways to add a resource attribute.

  1. By passing it as an environment variable if you are using the opentelemtry SDK or auto-instrumentation<service_name>,hostname=<host_name>
    replace the value of <service_name> with the actual service name and <host_name> with the actual hostname
  2. If you have a otel collector running on each host you can add a processor to add the hostname.
                - key: hostname
                  value: <hostname>
                  action: upsert
            processors: [attributes/add_hostname, batch]
    replace the value of <host_name> with the actual hostname

Missing Columns Issue

In case you are using signoz version 0.27 or newer and in the past you ran the migration 0.27 You may face missing columns issue if you are using distributed clickhouse with multiple shards.

To solve this issue, exec into all the shards and follow the steps below:

show create table signoz_logs.distributed_logs

If in one shard the name of a column is host_name and in other shard the name is attribute_string_host_name then run the following command

alter table signoz_logs.distributed_logs on cluster cluster rename column if exists host_name to attribute_string_host_name

Run the above command for all the column names which were not migrated.

K8s Attribute Filtering Issue in Logs

In the SigNoz charts releases v0.9.1, v0.10.0 and 0.10.1, some users who are facing issues querying the following selected fields.

  • k8s_container_name
  • k8s_namespace_name
  • k8s_pod_name
  • k8s_container_restart_count
  • k8s_pod_uid

If you have included any of the above to selected fields, and you get empty data when you filter using those fields then you will have to perform the following steps.

  • Exec into your clickhouse container

    kubectl exec -n platform -it chi-my-release-clickhouse-cluster-0-0-0 -- sh
    clickhouse client
  • Run the following queries

    use signoz_logs;
    show create table logs;
  • For the corresponding field, you will find a materialized column and an index. For example: k8s_namespace_name you will have k8s_namespace_name String MATERIALIZED attributes_string_value[indexOf(attributes_string_key, 'k8s_namespace_name')] CODEC(LZ4) and index INDEX k8s_namespace_name_idx k8s_namespace_name TYPE bloom_filter(0.01) GRANULARITY 64

  • You will have to delete the index and remove the materialized column

    alter table logs drop column k8s_namespace_name;
    alter table logs drop index k8s_namespace_name_idx;
  • Perform the above steps for all the k8s fields listed.

  • Once done truncate the attribute keys table

    truncate table logs_atrribute_keys;
  • Now you can go back to the UI and convert them back to the selected field, and filters will work as expected.