我的脚本从命令行顺利运行，但是，当我将其作为systemd.service启动时，出现以下错误：

iot_local.service - My iot_local Service
   Loaded: loaded (/lib/systemd/system/iot_local.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Sun 2018-04-01 23:06:45 UTC; 5s ago
  Process: 2436 ExecStart=/usr/bin/python /home/ubuntu/myTemp/iot_local.py (code=exited, status=1/FAILURE)
 Main PID: 2436 (code=exited, status=1/FAILURE)

Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 358, in resolve
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     service_name, region_name)
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/regions.py", line 122, in construct_endpoint
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     partition, service_name, region_name)
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/regions.py", line 135, in _endpoint_for_partition
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     raise NoRegionError()
Apr 01 23:06:45 ip-172-31-29-45 python[2436]: botocore.exceptions.NoRegionError: You must specify a region.
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Main process exited, code=exited, status=1/FAILURE
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Unit entered failed state.
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Failed with result 'exit-code'.

在这条线上似乎失败了：

DB=boto3.resourse('dynamodb')

如果我将区域添加为参数，则脚本稍后仍会失败，因为找不到凭据。因此，当我提供region，id和key作为参数时，一切正常：

boto3.resource('dynamodb', region_name='us-west-2', aws_access_key_id=ACCESS_ID, aws_secret_access_key=ACCESS_KEY)

明显的问题是，当此脚本作为服务运行时，它无法从~/.aws/config和获取信息~/.aws/credentials，我确保通过aws configure按此处所述运行来包含所有必需的信息。

[default]
aws_access_key_id=XXXXXXXXXXXXXX
aws_secret_access_key=YYYYYYYYYYYYYYYYYYYYYYYYYYY

我也尝试过这个：

export AWS_CONFIG_FILE="/home/ubuntu/.aws/config"

和这个

sudo chown root:root ~/.aws

但这没有帮助。为什么.service无法“看到”凭据文件的任何想法？