Uly.me

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Saving and Restoring iptables

iptables can be saved or loaded from a file. Here’s a way to do it.

Saving to a file

# Debian/Ubuntu
iptables-save > /etc/iptables/rules.v4
# Redhat/Centos/Rocky
iptables-save > /etc/sysconfig/iptables

Loading from a file

# Debian/Ubuntu
iptables-restore > /etc/iptables/rules.v4
# Redhat/Centos/Rocky
iptables-restore > /etc/sysconfig/iptables

Listing rules

iptables -L

GCP List of BMS Servers

Here’s how to list Bare Metal Servers in Google Cloud Platform via gcloud.

gcloud bms instances list --region REGION --project PROJECT

Result

NAME            ID                 PROJECT         REGION       MACHINE_TYPE           CLIENT_IPS    PRIVATE_IPS                    STATE
server-001      at-xxxxxxx-svr001  project-01      us-central1  o2-ultramem-896-metal  10.0.0.1      192.168.253.1,192.168.252.1    RUNNING
server-002      at-xxxxxxx-svr002  project-02      us-central1  o2-ultramem-896-metal  10.0.0.2      192.168.253.2,192.168.252.2    RUNNING

Obviously you can see the same from GCP’s Console.

History Without Line Numbers

Here’s how to display history without the line numbers.

history -w /dev/stdout

Result

cd /etc/httpd/conf
view httpd.conf 
vim wiki.conf 
vim ssl.conf

Python Boto3 S3 List Objects

How to list S3 objects using Python Boto3

import boto3
from sys import argv
bucket=argv[1]
s3 = boto3.resource('s3')
mybucket = s3.Bucket(bucket)
def list_buckets():
    print("List of Buckets: ")
    for bucket in s3.buckets.all():
        print(bucket.name)
def list_files():
    print("Buckets: The objects in the \"" + bucket + "\" buckets are ... ")
    for files in mybucket.objects.all():
        print(files.key)
def main():
    #list_buckets()
    list_files()
if __name__ == "__main__":
    main()

Running command

$ python test.py bucket-name    # with python
$ ./test.py bucket-name         # without python

Results

Buckets: The objects in the "bucket-name" are ....
abc.txt
def.txt

GCP Create Scheduled Snapshots

How to create scheduled snapshots in GCP.

gcloud compute resource-policies create snapshot-schedule hourly \
--description "my hourly schedule" \
--max-retention-days 7 \
--start-time 00:00 \
--hourly-schedule 1 \
--region us-central1 \
--on-source-disk-delete keep-auto-snapshots \
--storage-location US

Add snapshot schedule to a disk.

gcloud compute disks add-resource-policies disk-name \
--resource-policies hourly \
--zone us-central1-a
gcloud compute disks create disk-name \
--resource-policies hourly \
--zone us-central1-a

List snapshot schedules.

gcloud compute resource-policies list

Describe snapshot schedule.

gcloud compute resource-policies describe hourly

GCP List Disk Types

To list all disk types available in your project in all regions. Result is truncated.

$ gcloud compute disk-types list
NAME         ZONE                       VALID_DISK_SIZES
pd-balanced                             10GB-65536GB
pd-ssd                                  10GB-65536GB
pd-standard                             200GB-65536GB
pd-balanced                             10GB-65536GB
...

To list a specific region, use the filter option.

$ gcloud compute disk-types list --filter="zone~'us-central1'"
NAME         ZONE           VALID_DISK_SIZES
pd-balanced  us-central1-a  10GB-65536GB
pd-extreme   us-central1-a  500GB-65536GB
pd-ssd       us-central1-a  10GB-65536GB
pd-standard  us-central1-a  10GB-65536GB
pd-balanced  us-central1-b  10GB-65536GB
pd-extreme   us-central1-b  500GB-65536GB
pd-ssd       us-central1-b  10GB-65536GB
pd-standard  us-central1-b  10GB-65536GB
pd-balanced  us-central1-c  10GB-65536GB
pd-extreme   us-central1-c  500GB-65536GB
pd-ssd       us-central1-c  10GB-65536GB
pd-standard  us-central1-c  10GB-65536GB
pd-balanced  us-central1-f  10GB-65536GB
pd-extreme   us-central1-f  500GB-65536GB
pd-ssd       us-central1-f  10GB-65536GB
pd-standard  us-central1-f  10GB-65536GB
pd-balanced  us-central1-d  10GB-65536GB
pd-extreme   us-central1-d  500GB-65536GB
pd-ssd       us-central1-d  10GB-65536GB
pd-standard  us-central1-d  10GB-65536GB

To a list a specific region and local SSDs only.

gcloud compute disk-types list --filter="zone~'us-central1' AND name~'local-'"
NAME       ZONE           VALID_DISK_SIZES
local-ssd  us-central1-a  375GB-375GB
local-ssd  us-central1-b  375GB-375GB
local-ssd  us-central1-c  375GB-375GB
local-ssd  us-central1-f  375GB-375GB
local-ssd  us-central1-d  375GB-375GB

AWS display Lightsail snapshots

How to display Lightsail snapshots.

#!/bin/bash
displaysnapshots () {
  echo '--------------------------------------------------------'
  aws lightsail get-instance-snapshots --query 'instanceSnapshots[].[name]' --output text | sort
  echo '--------------------------------------------------------'
}
displaysnapshots

Result.

daily_ulyme_1637812801
daily_ulyme_1637899201
daily_ulyme_1637985601
daily_ulyme_1638072001

Adding timestamp to the output.

  aws lightsail get-instance-snapshots --query 'instanceSnapshots[].[name,createdAt]' --output text | sort

Result.

daily_ulyme_1637812801	1637812806.853
daily_ulyme_1637899201	1637899208.285
daily_ulyme_1637985601	1637985606.184
daily_ulyme_1638072001	1638072006.579

Convert Unix timestamp to iso8601. Edit your ~/.aws/config file. Add this line.

cli_timestamp_format = iso8601

Result.

daily_ulyme_1637812801	2021-11-25T04:00:06.853000+00:00
daily_ulyme_1637899201	2021-11-26T04:00:08.285000+00:00
daily_ulyme_1637985601	2021-11-27T04:00:06.184000+00:00
daily_ulyme_1638072001	2021-11-28T04:00:06.579000+00:00