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Last tested: Jan 21, 2019
This errors means this Looker instance is trying to use new encryption but we didn't find any of the relevant environment variables to set the backing keystore.
If you are trying to use AWS Key Management Service (KMS) you should ensure the environment variable LKR_AWS_CMK is pointed to a valid key alias as per KMS.
If you are trying to use a local backing key, ensure the environment variable LKR_MASTER_KEY_FILE is set and pointed to a file containing a 32 byte key.
Even if echo $ENV_VARIABLE shows the variable is set, try setting it explicitly in the startup script to ensure it is set where the jar is being started.