[beam_PostCommit_Python_Verify][test_hourly_team_score_it][Flake] Failed to install packages

boot.go failed to install SDK.

Failing job url:

https://builds.apache.org/job/beam_PostCommit_Python_Verify/5920/

Relevant log:

Stackdriver logs:
https://pantheon.corp.google.com/logs/viewer?resource=dataflow_step%2Fjob_id%2F2018-09-07_11_04_49-10526452128675467543&logName=projects%2Fapache-beam-testing%2Flogs%2Fdataflow.googleapis.com%252Fworker-startup&interval=NO_LIMIT&project=apache-beam-testing&minLogLevel=500&expandAll=false&timestamp=2018-09-07T19:12:48.643000000Z&customFacets=&limitCustomFacetWidth=true&scrollTimestamp=2018-09-07T18:13:26.584160000Z&dateRangeUnbound=forwardInTime

 

Worker startup:

Installing setup packages ... 

Executing: /usr/local/bin/pip install /var/opt/google/dataflow/dataflow_python_sdk.tar[gcp] 

Traceback (most recent call last): 

File "/usr/local/bin/pip", line 7, in <module>

from pip._internal import main 

ImportError : No module named pip._internal

/usr/local/bin/pip failed with exit status 1

Dataflow base path override: https://dataflow.googleapis.com/

 

2018-09-07 11:12:47.377 PDTFailed to install packages: failed to install SDK: exit status 1
{
insertId: "237402094728839677:887122:0:16965" 
jsonPayload: 

{ line: "boot.go:145"  message: "Failed to install packages: failed to install SDK: exit status 1" }

labels: 

{ compute.googleapis.com/resource_id: "237402094728839677"  compute.googleapis.com/resource_name: "beamapp-jenkins-090718044-09071104-8yaz-harness-dzk6"  compute.googleapis.com/resource_type: "instance"  dataflow.googleapis.com/job_id: "2018-09-07_11_04_49-10526452128675467543"  dataflow.googleapis.com/job_name: "beamapp-jenkins-0907180442-302722"  dataflow.googleapis.com/region: "us-central1" }

logName: "projects/apache-beam-testing/logs/dataflow.googleapis.com%2Fworker-startup" 
receiveTimestamp: "2018-09-07T18:12:49.639606153Z" 
resource: {
labels: 

{ job_id: "2018-09-07_11_04_49-10526452128675467543"  job_name: "beamapp-jenkins-0907180442-302722"  project_id: "apache-beam-testing"  region: "us-central1"  step_id: "" }

type: "dataflow_step" }
severity: "CRITICAL" 
timestamp: "2018-09-07T18:12:47.377871Z" }