I'm trying to use Netmiko to log into a Cisco NXOS device and copy its startup config to another NXOS device.
Here's the script:
core1 = {"device_type":"cisco_nxos","host":"192.168.254.51","username":"admin","password":"admin"}
net_connect = ConnectHandler(**core1)
net_connect.enable()
cmds = [["copy start scp://admin:admin#192.168.254.55/my-backup.cfg vrf management",r"Password"],["admin",""]]
r = net_connect.send_multiline(cmds)
net_connect.disconnect()
The code seems to work, it actually copies the config, but after some delay (the timeout) it throws an exception:
netmiko.exceptions.ReadTimeout:
Pattern not detected: 'admin' in output.
I cannot figure out what I'm doing wrong. It says pattern "admin" not detected, but it definitely sent admin as the password. Maybe because the input is hidden (it's a password) Netmiko can't pick up the input?
Session log:
Prod-CORE1#
Prod-CORE1# terminal width 511
Prod-CORE1# terminal length 0
Prod-CORE1#
Prod-CORE1#
Prod-CORE1#
Prod-CORE1# copy start scp://********:********#192.168.254.55/my-backup.cfg vrf management
Outbound-ReKey for 192.168.254.55:22
Inbound-ReKey for 192.168.254.55:22
User Access Verification
Password:
Prod-CORE1-startup-config 0% 0 0.0KB/s --:-- ETA
Prod-CORE1-startup-config 100% 5153 544.0KB/s 00:00
Copy complete, now saving to disk (please wait)...
Copy complete.
Prod-CORE1#
Prod-CORE1# exit
Is there a way to handle hidden inputs with Netmiko or send a "blind" command?
SCP copies on NXOS seem to ignore the username:password format and still prompt for a password so I can't run the copy on a single line.
I just discovered the cmd_verify=False option.
I did this:
r = net_connect.send_multiline(cmds,cmd_verify=False)
and it works fine now
Related
I am trying to use pktmon(built-in windows packet analyzer). However from the documentation they mention that by default packet size is limited to 128 bytes but can be increase with the following command pktmon start --etw -p 0.
But running that command gives me this error Error: '0' is not a valid event provider Id. what could be wrong?
So far I've not seen anything helpful on the internet.
Most of the examples on the internet show
pktmon start --etw -p 0 -c 1
The -p doesn't seem to work and also the -c.
So what worked for me is
pktmon start --etw --pkt-size 0 --comp 1
From the utility help:
--pkt-size
Number of bytes to log from each packet. To always log the entire
packet set this to 0. Default is 128 bytes.
I'm using rsync to backup some data from a remote host.
this is how I'm using the rsync cmd:
rsync --dry-run -avhi -e ssh --include-from=/home/rsync_list/test.txt root#10.10.4.61:/ /mnt/BACKUP/my_BACKUP/
this is the file /home/rsync_list/test.txt
+ /usr/acs/conf/**
+ /usr/acs/bin/**
+ /raid0/opmdps/TEMP_folder/**
- *
I want to copy only the listed folders excluding the remaining files.
I always get
receiving file list ... done
sent 103 bytes received 48 bytes 302.00 bytes/sec
total size is 0 speedup is 0.00 (DRY RUN)
Could you tell me what I'm doing wrong? How should I write the rsync command if I would like to sync, for example, only /raid0/opmdps/TEMP_folder/ without its subfolders?
I wonder if you really only tried with the command you posted?
Not only you are using "--dry-run" option, even the output indicates this:
total size is 0 speedup is 0.00 (DRY RUN)
Please consult the manpage:
-n, --dry-run perform a trial run with no changes made
https://linux.die.net/man/1/rsync
May I suggest you give it a run without --dry-run?
I've created a simple go script: https://gist.github.com/kbl/86ed3b2112eb80522949f0ce574a04e3
It's fetching some xml from the internet and then starts X goroutines. The X depends on file content. In my case it was 1700 goroutines.
My first execution finished with:
$ go run mathandel1.go
2018/01/27 14:19:37 Get https://www.boardgamegeek.com/xmlapi/boardgame/162152?pricehistory=1&stats=1: dial tcp 72.233.16.130:443: socket: too many open files
2018/01/27 14:19:37 Get https://www.boardgamegeek.com/xmlapi/boardgame/148517?pricehistory=1&stats=1: dial tcp 72.233.16.130:443: socket: too many open files
exit status 1
I've tried to increase ulimit to 2048.
Now I'm getting different error, script is the same thou:
$ go build mathandel1.go
# command-line-arguments
/usr/local/go/pkg/tool/linux_amd64/link: flushing $WORK/command-line-arguments/_obj/exe/a.out: write $WORK/command-line-arguments/_obj/exe/a.out: file too large
What is causing that error? How can I fix that?
You ran ulimit 2048 which changed the maximum file size.
From man bash(1), ulimit section:
If no option is given, then -f is assumed.
This means that you now set the maximum file size to 2048 bytes, that's probably not enough for.... anything.
I'm guessing you meant to change the limit for number of open file descriptors. For this, you want to run:
ulimit -n 2048
As for the original error (before changing the maximum file size), you're launching 1700 goroutines, each performing a http get. Each creates a connection, using a tcp socket. These are covered by the open file descriptor limit.
Instead, you should be limiting the number of concurrent downloads. This can be done with a simple worker pool pattern.
I am trying to analyse a randomly crashing application.To get some details of the process i am implementing a script like below
procID=$(ps -aef|grep app|awk '{print $2}')
top -p $procID -b -d 10 > test.log
In this case top command will execute for every 10 sec and write to test.log. Planning to run it indefinitely, but I want to flush out the contents of test.log each time top command writes some value to it. How can I modify the script accordingly ?
To avoid your log getting too big, I suggest you use logrotate instead. In short, logrotate creates a cronjob that will "rotate" your log file upon a condition (one file per day, rotate when the file reaches a given size, etc.). You can also choose to keep the X last rotated logs.
This is what is used for lastmessage and the other linux log files (hence the .log.1, .log.2 etc.)
Here is a basic way to make it work:
Create a configuration for your file in /etc/logrotate.d. For example:
# /etc/logrotate.d/test
/var/log/test.log {
size 4M
create 770 somegroup someuser
rotate 4
missingok
copytruncate
}
What it says:
size 4M: rotate file after it reaches 4M in size
create ...: create new file with the given permisions (replace somegroup someuser by your usergroup and username)
rotate 4: keep the last 4 log files (test.log, test.log.1 etc)
missingOk an copyTruncate: avoid some errors (see the doc for more info)
Check that your file is correct by executing:
sudo logrotate /etc/logrotate.d/test
enjoy.
More about logrotate: https://support.rackspace.com/how-to/understanding-logrotate-utility/
The problem
SNMPD is correctly delegating SNMP polling requests to another program but the response from that program is not valid. A manual run of the program with the same arguments is responding correctly.
The detail
I've installed the correct LSI raid drivers on a server and want to configure SNMP. As per the instructions, I've added the following to /etc/snmp/snmpd.conf to redirect SNMP polling requests with a given OID prefix to a program:
pass .1.3.6.1.4.1.3582 /usr/sbin/lsi_mrdsnmpmain
It doesn't work correctly for SNMP polling requests:
snmpget -v1 -c public localhost .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.1
I get the following response:
Error in packet
Reason: (noSuchName) There is no such variable name in this MIB.
Failed object: SNMPv2-SMI::enterprises.3582.5.1.4.2.1.2.1.32.1
What I've tried
SNMPD passes two arguments, -g and <oid> and expects a three line response <oid>, <data-type> and <data-value>.
If I manually run the following:
/usr/sbin/lsi_mrdsnmpmain -g .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0
I correctly get a correct three line response:
.1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0
integer
30
This means that the pass command is working correctly and the /usr/sbin/lsi_mrdsnmpmain program is working correctly in this example
I tried replacing /usr/sbin/lsi_mrdsnmpmain with a bash script. The bash script delegates the call and logs the supplied arguments and output from the delegated call:
#!/bin/bash
echo "In: '$#" > /var/log/snmp-pass-test
RETURN=$(/usr/sbin/lsi_mrdsnmpmain $#)
echo "$RETURN"
echo "Out: '$RETURN'" >> /var/log/snmp-pass-test
And modified the pass command to redirect to the bash script. If I run the bash script manually /usr/sbin/snmp-pass-test -g .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0 I get the correct three line response as I did when I ran /usr/sbin/lsi_mrdsnmpmain manually and I get the following logged:
In: '-g .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0
Out: '.1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0
integer
30'
When I rerun the snmpget test, I get the same Error in packet... error and the bash script's logging shows that the captured delegated call output is empty:
In: '-g .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.0
Out: ''
If I modify the bash script to only echo an empty line I also get the same Error in packet... message.
I've also tried ensuring that the environment variables that are present when I manually call /usr/sbin/lsi_mrdsnmpmain are the same for the bash script but I get the same empty output.
Finally, my questions
Why would the bash script behave differently in these two scenarios?
Is it likely that the problem that exists with the bash scripts is the same as originally noticed (manually running program has different output to SNMPD run program)?
Updates
eewanco's suggestions
What user is running the program in each scenario?
I added echo "$(whoami)" > /var/log/snmp-pass-test to the bash script and root was added to the logs
Maybe try executing it in cron
Adding the following to root's crontab and the correct three line response was logged:
* * * * * /usr/sbin/lsi_mrdsnmpmain -g .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.1 >> /var/log/snmp-test-cron 2>&1
Grisha Levit's suggestion
Try logging the stderr
There aren't any errors logged
Checking /var/log/messages
When I run it via SNMPD, I get MegaRAID SNMP AGENT: Error in getting Shared Memory(lsi_mrdsnmpmain) logged. When I run it directly, I don't. I've done a bit of googling and I may need lm_sensors installed; I'll try this.
I installed lm_sensors & compat-libstdc++-33.i686 (the latter because it said it was a pre-requisite from the instructions and I was missing it), uninstalled and reinstalled the LSI drivers and am experiencing the same issue.
SELinux
I accidently stumbled upon a page about extending snmpd with scripts and it says to check the script has the right SELinux context. I ran grep AVC /var/log/audit/audit.log | grep snmp before and after running a snmpget and the following entry is added as a direct result from running snmpget:
type=AVC msg=audit(1485967641.075:271): avc: denied { unix_read unix_write } for pid=5552 comm="lsi_mrdsnmpmain" key=558265 scontext=system_u:system_r:snmpd_t:s0 tcontext=system_u:system_r:initrc_t:s0 tclass=shm
I'm now assuming that SELinux is causing the call to fail; I'll dig further...see answer for solution.
strace (eewanco's suggestion)
Try using strace with and without snmp and see if you can catch a system call failure or some additional hints
For completeness, I wanted to see if strace would have hinted that SELinux was denying. I had to remove the policy packages using semodule -r <policy-package-name> to reintroduce the problem then ran the following:
strace snmpget -v1 -c public localhost .1.3.6.1.4.1.3582.5.1.4.2.1.2.1.32.1 >> strace.log 2>&1
The end of strace.log is as follows and unless I'm missing something, it doesn't seem to provide any hints:
...
sendmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(161), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)= [{"0;\2\1\0\4\20public\240$\2\4I\264-m\2"..., 61}], msg_controllen=32, {cmsg_len=28, cmsg_level=SOL_IP, cmsg_type=, ...}, msg_flags=0}, MSG_DONTWAIT|MSG_NOSIGNAL) = 61
select(4, [3], NULL, NULL, {0, 999997}) = 1 (in [3], left {0, 998475})
brk(0xab9000) = 0xab9000
recvmsg(3, {msg_name(16)={sa_family=AF_INET, sin_port=htons(161), sin_addr=inet_addr("127.0.0.1")}, msg_iov(1)= [{"0;\2\1\0\4\20public\242$\2\4I\264-m\2"..., 65536}], msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 61
write(2, "Error in packet\nReason: (noSuchN"..., 81Error in packet
Reason: (noSuchName) There is no such variable name in this MIB.
) = 81
write(2, "Failed object: ", 15Failed object: ) = 15
write(2, "SNMPv2-SMI::enterprises.3582.5.1"..., 48SNMPv2- SMI::enterprises.3582.5.1.4.2.1.2.1.32.1
) = 48
write(2, "\n", 1
) = 1
brk(0xaa9000) = 0xaa9000
close(3) = 0
exit_group(2) = ?
+++ exited with 2 +++
It was SELinux that was denying snmpd a delegated call to /usr/sbin/lsi_mrdsnmpmain (and probably beyond).
To identify it, I ran grep AVC /var/log/audit/audit.log and for each entry, I ran the following:
echo "<grepped-output>" | audit2allow -a -M <filename>
This creates a SELinux policy package that should allow the delegated call through. The package is then loaded using the following:
semodule -i <filename>.pp
I had to do this 5 times as there were different causes of denial (unix_read unix_write, associate, read write). I'll look to combine the modules into one.
Now when I run snmpget I get the correct delegated output:
SNMPv2-SMI::enterprises.3582.5.1.4.2.1.2.1.32.1 = INTEGER: 34