Bypass instance limit check if AWS's API doesn't provide the information (#1439)

Author: deliahu

pkg/lib/aws/servicequotas.go

@@ -23,6 +23,7 @@ import (
 "github.com/aws/aws-sdk-go/aws"
 "github.com/aws/aws-sdk-go/service/servicequotas"
 "github.com/cortexlabs/cortex/pkg/lib/errors"
+"github.com/cortexlabs/cortex/pkg/lib/pointer"
 "github.com/cortexlabs/cortex/pkg/lib/sets/strset"
 )
 
@@ -42,7 +43,7 @@ func (c *Client) VerifyInstanceQuota(instanceType string) error {
 instancePrefix = "standard"
 }
 
-var cpuLimit int
+var cpuLimit *int
 err := c.ServiceQuotas().ListServiceQuotasPages(
 &servicequotas.ListServiceQuotasInput{
 ServiceCode: aws.String("ec2"),
@@ -62,7 +63,7 @@ func (c *Client) VerifyInstanceQuota(instanceType string) error {
 }
 
 if strings.ToLower(*metricClass) == instancePrefix+"/ondemand" {
-cpuLimit = int(*quota.Value) // quota is specified in number of vCPU permitted per family
+cpuLimit = pointer.Int(int(*quota.Value)) // quota is specified in number of vCPU permitted per family
 return false
 }
 }
@@ -73,7 +74,7 @@ func (c *Client) VerifyInstanceQuota(instanceType string) error {
 return errors.WithStack(err)
 }
 
-if cpuLimit == 0 {
+if cpuLimit != nil && *cpuLimit == 0 {
 return ErrorInstanceTypeLimitIsZero(instanceType, c.Region)
 }