Troubleshooting using Kubectl

Kubernetes provides a command line tool for communicating with a Kubernetes cluster’s control plane, using the Kubernetes API.

This document describes how one can use kubectl to debug any issues with the cluster.

Diving into the Components

Using kubectl, one can inspect the cluster’s current state. When Workflow is installed with helm, Workflow is installed into the drycc namespace. To inspect if Workflow is running, run:

$ kubectl --namespace=drycc get pods
NAME                          READY     STATUS              RESTARTS   AGE
drycc-builder-gqum7            0/1       ContainerCreating   0          4s
drycc-controller-h6lk6         0/1       ContainerCreating   0          4s
drycc-controller-celery-cmxxn  0/3       ContainerCreating   0          4s
drycc-database-56v39           0/1       ContainerCreating   0          4s
drycc-logger-fluentbit-xihr1   0/1       Pending             0          2s
drycc-logger-grupg             0/1       ContainerCreating   0          3s
drycc-storage-c2exb            0/1       Pending             0          3s
drycc-monitor-grafana-9ccur    0/1       Pending             0          3s
drycc-monitor-telegraf-dc3y3   0/1       Pending             0          2s
drycc-registry-5bor6           0/1       Pending             0          3s
drycc-rabbitmq-0               0/1       ContainerCreating   0          3s

!!! tip To save precious keystrokes, alias kubectl --namespace=drycc to kd so it is easier to type in the future.

To fetch the logs of a specific component, use kubectl logs:

$ kubectl --namespace=drycc logs drycc-controller-h6lk6
system information:
Django Version: 1.9.6
Python 3.5.1
addgroup: gid '0' in use
Django checks:
System check identified no issues (2 silenced).
[...]

To dive into a running container to inspect its environment, use kubectl exec:

$ kubectl --namespace=drycc exec -it drycc-database-56v39 gosu postgres psql
psql (13.4 (Debian 13.4-1.pgdg100+1))
Type "help" for help.

postgres=# \l
                                                List of databases
     Name          |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges
-------------------+----------+----------+------------+------------+-----------------------
 drycc_controller  | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 drycc_passport    | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 postgres          | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 template0         | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
                   |          |          |            |            | postgres=CTc/postgres
 template1         | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
                   |          |          |            |            | postgres=CTc/postgres
(4 rows)
postgres=# \connect drycc_controller
You are now connected to database "drycc_controller" as user "postgres".
drycc_controller=# \dt
                                 List of relations
 Schema |              Name              | Type  |      Owner
--------+--------------------------------+-------+-------------------
 public | api_app                        | table | drycc_controller
 public | api_build                      | table | drycc_controller
 public | api_certificate                | table | drycc_controller
 public | api_config                     | table | drycc_controller
 public | api_domain                     | table | drycc_controller
 public | api_key                        | table | drycc_controller
 public | api_push                       | table | drycc_controller
 public | api_release                    | table | drycc_controller
 public | auth_group                     | table | drycc_controller
 --More--
 drycc_controller=# SELECT COUNT(*) from api_app;
 count
-------
     0
(1 row)