I experience the same issue. It seems the runner is not collecting the logs, or not posting the logs to the controller. After collecting the log files, i reverted to the previous configuration and the collection of the logging works.
I expect the API call /rpc/v2/step/938/logs/upload containing the log lines, however the collection is not working. The only information passed on to the controller is “[{“pos”:0,“out”:”",“time”:6}]" this is the same for all steps.
I’ve studied the debug article and inspected the runner source code, but i couldn’t find the part of the code that retrieves the log from the pod. I hope someone with knowledge of the runner can give us some guidelines on how to proceed, as i would really like to have the runner up and running 
Below i’ve posted:
- the drone pipeline
- The output of the controller
- Some output of the runner
I’ve created a .drone.yaml file with a few steps to test:
kind: pipeline
type: kubernetes
name: default
platform:
os: linux
arch: arm64
clone:
disable: true
steps:
- name: greeting
image: alpine
commands:
- echo hello
- echo world
- name: foo
image: alpine
commands:
- touch hello.txt
- name: bar
image: alpine
commands:
- ls hello.txt
- name: clone-google-kaniko
image: drone/git
commands:
- git clone https://github.com/GoogleContainerTools/kaniko /go/src/github.com/GoogleContainerTools/kaniko
Output of the controller
time="2020-01-12T21:52:41Z" level=debug fields.time="2020-01-12T21:52:41Z" latency=8.61918ms method=GET remote="10.42.2.1:56434" request=/ request-id=1WJRxzSikVGxANSqoayxJpWGRPb
time="2020-01-12T21:52:41Z" level=debug msg="manager: request queue item" arch= kernel= kind=pipeline os= type=kubernetes variant=
time="2020-01-12T21:52:42Z" level=debug msg="webhook parsed" commit=994c6f55d5c0c9cf716f2c9049a8bcd83a79e50f event=push name=drone-test namespace=Rick-Jongbloed
time="2020-01-12T21:52:42Z" level=debug msg="trigger: received" commit=994c6f55d5c0c9cf716f2c9049a8bcd83a79e50f event=push ref=refs/heads/master repo=Rick-Jongbloed/drone-test
time="2020-01-12T21:52:42Z" level=debug fields.time="2020-01-12T21:52:42Z" latency=637.907431ms method=POST remote="10.42.0.35:48966" request=/hook request-id=1WJRy5BjtYXLDgZwl6Axho9zJxw
time="2020-01-12T21:52:42Z" level=debug msg="manager: request queue item" arch= kernel= kind=pipeline os= type=kubernetes variant=
time="2020-01-12T21:52:42Z" level=debug msg="manager: accept stage" machine=drone-runner-arm stage-id=298
time="2020-01-12T21:52:42Z" level=debug msg="manager: accept stage" machine=drone-runner-arm stage-id=298
time="2020-01-12T21:52:42Z" level=debug msg="manager: request queue item" arch= kernel= kind=pipeline os= type=kubernetes variant=
time="2020-01-12T21:52:42Z" level=debug msg="manager: stage accepted" machine=drone-runner-arm stage-id=298
time="2020-01-12T21:52:42Z" level=debug msg="manager: fetching stage details" step-id=298
time="2020-01-12T21:52:42Z" level=debug msg="manager: stage processed by another agent" error="Optimistic Lock Error" machine=drone-runner-arm stage-id=298
time="2020-01-12T21:52:43Z" level=debug msg="manager: updating step status" step.id=938 step.name=greeting step.status=running
time="2020-01-12T21:52:51Z" level=debug fields.time="2020-01-12T21:52:51Z" latency=10.049557ms method=GET remote="10.42.2.1:56438" request=/ request-id=1WJRzKam6xAZSiNvYPJgzWhkVEd
time="2020-01-12T21:53:01Z" level=debug fields.time="2020-01-12T21:53:01Z" latency=9.669838ms method=GET remote="10.42.2.1:56440" request=/ request-id=1WJS0XmTcEcbdqMXvpjWRovYphK
time="2020-01-12T21:53:04Z" level=debug msg="manager: updating step status" step.id=938 step.name=greeting step.status=success
time="2020-01-12T21:53:04Z" level=debug msg="manager: updating step status" step.id=939 step.name=foo step.status=running
time="2020-01-12T21:53:11Z" level=debug fields.time="2020-01-12T21:53:11Z" latency=12.448756ms method=GET remote="10.42.2.1:56442" request=/ request-id=1WJS1lsbQJN8gF1qjmL6yX3vrmR
time="2020-01-12T21:53:12Z" level=debug msg="manager: context canceled" arch= kernel= kind=pipeline os= type=kubernetes variant=
time="2020-01-12T21:53:14Z" level=debug msg="manager: updating step status" step.id=939 step.name=foo step.status=success
time="2020-01-12T21:53:14Z" level=debug msg="manager: updating step status" step.id=940 step.name=bar step.status=running
time="2020-01-12T21:53:20Z" level=debug msg="manager: updating step status" step.id=940 step.name=bar step.status=success
time="2020-01-12T21:53:20Z" level=debug msg="manager: updating step status" step.id=941 step.name=clone-google-kaniko step.status=running
time="2020-01-12T21:53:21Z" level=debug fields.time="2020-01-12T21:53:21Z" latency=9.803758ms method=GET remote="10.42.2.1:56446" request=/ request-id=1WJS2zScvQhrLVVTOnlNJeOlFZg
time="2020-01-12T21:53:22Z" level=debug msg="manager: request queue item" arch= kernel= kind=pipeline os= type=kubernetes variant=
time="2020-01-12T21:53:31Z" level=debug fields.time="2020-01-12T21:53:31Z" latency=8.488093ms method=GET remote="10.42.2.1:56448" request=/ request-id=1WJS4Hh5xMphfp8ZtruxycIv4An
time="2020-01-12T21:53:37Z" level=debug msg="manager: updating step status" step.id=941 step.name=clone-google-kaniko step.status=success
time="2020-01-12T21:53:38Z" level=debug msg="manager: stage is complete. teardown" stage.id=298
time="2020-01-12T21:53:38Z" level=debug msg="manager: build is finished, teardown" build.id=307 build.number=12 repo.id=30 stage.id=298
time="2020-01-12T21:53:41Z" level=debug fields.time="2020-01-12T21:53:41Z" latency=9.73309ms method=GET remote="10.42.2.1:56450" request=/ request-id=1WJS5WLoXgWsLgjf73yU2juipca
A selection of the output of the runner:(from running to posting the logs of stage 1)
{"id":298,"repo_id":0,"build_id":307,"number":1,"name":"default","kind":"pipeline","type":"kubernetes","status":"running","errignore":false,"exit_code":0,"machine":"drone-runner-arm","os":"linux","arch":"arm64","started":1578865963,"stopped":0,"created":1578865962,"updated":1578865963,"version":3,"on_success":true,"on_failure":false,"steps":[{"id":938,"step_id":298,"number":1,"name":"greeting","status":"pending","exit_code":0,"version":1},{"id":939,"step_id":298,"number":2,"name":"foo","status":"pending","exit_code":0,"version":1},{"id":940,"step_id":298,"number":3,"name":"bar","status":"pending","exit_code":0,"version":1},{"id":941,"step_id":298,"number":4,"name":"clone-google-kaniko","status":"pending","exit_code":0,"version":1}]}
time="2020-01-12T21:52:43Z" level=debug msg="updated stage to running" build.id=307 build.number=12 repo.id=30 repo.name=drone-test repo.namespace=Rick-Jongbloed stage.id=298 stage.name=default stage.number=1 thread=4
PUT /rpc/v2/step/938 HTTP/1.1
Host: drone-controller
User-Agent: Go-http-client/1.1
Content-Length: 120
X-Drone-Token: 33eb94a450d8075023820bab4177d951
Accept-Encoding: gzip
{"id":938,"step_id":298,"number":1,"name":"greeting","status":"running","exit_code":0,"started":1578865963,"version":1}
HTTP/1.1 200 OK
Content-Length: 120
Cache-Control: no-cache, no-store, must-revalidate, private, max-age=0
Content-Type: text/plain; charset=utf-8
Date: Sun, 12 Jan 2020 21:52:43 GMT
Expires: Thu, 01 Jan 1970 00:00:00 UTC
Pragma: no-cache
X-Accel-Expires: 0
{"id":938,"step_id":298,"number":1,"name":"greeting","status":"running","exit_code":0,"started":1578865963,"version":2}
POST /rpc/v2/step/938/logs/batch HTTP/1.1
Host: drone-controller
User-Agent: Go-http-client/1.1
Content-Length: 30
X-Drone-Token: 33eb94a450d8075023820bab4177d951
Accept-Encoding: gzip
[{"pos":0,"out":"","time":6}]
HTTP/1.1 200 OK
Content-Length: 0
Cache-Control: no-cache, no-store, must-revalidate, private, max-age=0
Date: Sun, 12 Jan 2020 21:52:51 GMT
Expires: Thu, 01 Jan 1970 00:00:00 UTC
Pragma: no-cache
X-Accel-Expires: 0
POST /rpc/v2/step/938/logs/upload HTTP/1.1
Host: drone-controller
User-Agent: Go-http-client/1.1
Content-Length: 30
X-Drone-Token: 33eb94a450d8075023820bab4177d951
Accept-Encoding: gzip
[{"pos":0,"out":"","time":6}]
HTTP/1.1 200 OK
Content-Length: 0
Cache-Control: no-cache, no-store, must-revalidate, private, max-age=0
Date: Sun, 12 Jan 2020 21:53:04 GMT
Expires: Thu, 01 Jan 1970 00:00:00 UTC
Pragma: no-cache
X-Accel-Expires: 0
PUT /rpc/v2/step/938 HTTP/1.1
Host: drone-controller
User-Agent: Go-http-client/1.1
Content-Length: 141
X-Drone-Token: 33eb94a450d8075023820bab4177d951
Accept-Encoding: gzip