C++
C++
SSH Parallel Remote Commands on Multiple Servers
See more SSH Examples
Demonstrates running the same command on several servers simultaneously. It is simply a matter of using one Ssh object per server, starting the command on each with QuickCmdSend, and then polling each connection with QuickCmdCheck until all have finished.
Background: This is the fan-out pattern behind configuration-management and monitoring tools: query or update a whole fleet in roughly the time the slowest single host takes, rather than the sum of all of them. Each server needs its own object because each has its own connection and authentication state. Note that results come back in whatever order the servers finish, which is why the example tracks completion per connection. Production code would keep the objects in arrays instead of repeating the logic per server.
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#include <CkSsh.h>
void ChilkatSample(void)
{
bool success = false;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// Demonstrates running the same command on several servers simultaneously. It is simply a
// matter of using one Ssh object per server.
CkSsh ssh1;
CkSsh ssh2;
CkSsh ssh3;
int port = 22;
// Normally you would not hard-code the password in source. You should instead obtain it
// from an interactive prompt, environment variable, or a secrets vault.
const char *password = "mySshPassword";
success = ssh1.Connect("ssh-server1.example.com",port);
if (success == false) {
std::cout << ssh1.lastErrorText() << "\r\n";
return;
}
success = ssh1.AuthenticatePw("mySshLogin",password);
if (success == false) {
std::cout << ssh1.lastErrorText() << "\r\n";
return;
}
success = ssh2.Connect("ssh-server2.example.com",port);
if (success == false) {
std::cout << ssh2.lastErrorText() << "\r\n";
return;
}
success = ssh2.AuthenticatePw("mySshLogin",password);
if (success == false) {
std::cout << ssh2.lastErrorText() << "\r\n";
return;
}
success = ssh3.Connect("ssh-server3.example.com",port);
if (success == false) {
std::cout << ssh3.lastErrorText() << "\r\n";
return;
}
success = ssh3.AuthenticatePw("mySshLogin",password);
if (success == false) {
std::cout << ssh3.lastErrorText() << "\r\n";
return;
}
// This command sleeps for 5 seconds and then prints the system date/time, making the parallel
// execution easy to observe.
const char *cmd = "sleep 5; date";
// Start the command on each server. QuickCmdSend returns immediately.
int channel1 = ssh1.QuickCmdSend(cmd);
if (channel1 < 0) {
std::cout << ssh1.lastErrorText() << "\r\n";
return;
}
int channel2 = ssh2.QuickCmdSend(cmd);
if (channel2 < 0) {
std::cout << ssh2.lastErrorText() << "\r\n";
return;
}
int channel3 = ssh3.QuickCmdSend(cmd);
if (channel3 < 0) {
std::cout << ssh3.lastErrorText() << "\r\n";
return;
}
// The command is now running on all three servers at once. Poll each connection until every
// command has finished. (Production code would keep the objects in arrays rather than
// repeating the logic.)
int pollTimeoutMs = 50;
int numFinished = 0;
bool finished1 = false;
bool finished2 = false;
bool finished3 = false;
while (numFinished < 3) {
if (!finished1) {
int ch1 = ssh1.QuickCmdCheck(pollTimeoutMs);
if (ch1 == -2) {
std::cout << ssh1.lastErrorText() << "\r\n";
return;
}
if (ch1 >= 0) {
std::cout << "---- ssh1 channel " << ch1 << " finished ----" << "\r\n";
const char *out1 = ssh1.getReceivedText(ch1,"utf-8");
if (ssh1.get_LastMethodSuccess() == false) {
std::cout << ssh1.lastErrorText() << "\r\n";
return;
}
std::cout << out1 << "\r\n";
finished1 = true;
numFinished = numFinished + 1;
}
}
if (!finished2) {
int ch2 = ssh2.QuickCmdCheck(pollTimeoutMs);
if (ch2 == -2) {
std::cout << ssh2.lastErrorText() << "\r\n";
return;
}
if (ch2 >= 0) {
std::cout << "---- ssh2 channel " << ch2 << " finished ----" << "\r\n";
const char *out2 = ssh2.getReceivedText(ch2,"utf-8");
if (ssh2.get_LastMethodSuccess() == false) {
std::cout << ssh2.lastErrorText() << "\r\n";
return;
}
std::cout << out2 << "\r\n";
finished2 = true;
numFinished = numFinished + 1;
}
}
if (!finished3) {
int ch3 = ssh3.QuickCmdCheck(pollTimeoutMs);
if (ch3 == -2) {
std::cout << ssh3.lastErrorText() << "\r\n";
return;
}
if (ch3 >= 0) {
std::cout << "---- ssh3 channel " << ch3 << " finished ----" << "\r\n";
const char *out3 = ssh3.getReceivedText(ch3,"utf-8");
if (ssh3.get_LastMethodSuccess() == false) {
std::cout << ssh3.lastErrorText() << "\r\n";
return;
}
std::cout << out3 << "\r\n";
finished3 = true;
numFinished = numFinished + 1;
}
}
}
ssh1.Disconnect();
ssh2.Disconnect();
ssh3.Disconnect();
}